The reason to preheat the oven is to brown it quickly without drying out the outside and overcooking inside.
The same exact reason you put steak on a hot pan, not cold. If you put it on cold pan it would be cooked through before you get any browning on the outside.
If you take too long baking bread the outside will be dried out, not crisped. Not everybody sees the difference but at least for me it is pretty significant.
Consumer ovens are pitifully underpowered for the most part and will take forever to bring oven to temperature with a large wet mass inside. Even if the oven is preheated the temperature instantly dips very significantly when you put your dough in.
The reason they do it in professional setting is because they don't have time to cool it down and then get it back up to temperature. Another reason is you want repeatable results and not depending on starting temperature.
As to the safety, as long as you are not super clumsy just general common sense is enough to prevent any burns. Don't touch the oven. Use oven mittens. Use extra long mittens if you don't feel safe. Do not operate on the dough while it is inside the oven (tray out, then do whatever you want, tray in). If you use steam to bake (which I do) make sure you understand where the steam goes so you avoid the areas where the hot 200C steam will be when you open oven door so you don't burn your face and hands (the answer: it goes up). Keep your small kids occupied somewhere else so they don't feel the need to have fun with hot oven while baking and after while it is still hot.
If you use a good quality dutch oven with a well-fitting lid, drying out isn’t an issue at all. In fact you have to take the lid off for the last 10-20 minutes to brown the crust at all.
However, getting your dough into a preheated dutch oven is fiddly and a little dangerous. That’s why I recommend just starting from cold.
Hm, I'm willing to pay hundreds of dollars to buy a special pan that doesn't preheat, so I could cook the steak through first, then sear. Maybe I've been doing this wrong! Or maybe there's a Cinder Grill rep here that can get me a special deal for shilling their product :)
"The Food Lab" is also a good book, if you like diving deeper on this sort of thing.
> pay hundreds of dollars to buy a special pan that doesn't preheat, so I could cook the steak through first
You don't need hundreds, just ~$100 for an inexpensive sous vide cooker with integrated thermometer & temp regulation [0]
You can put the meet in a zip lock bag and suck the air out with a straw and have it work just fine if you want to avoid the added expense of vacuum bags. When the meat hits the desired temp, remove, unwrap, sear the outside, and voila!
Everybody has one. Most ovens can get down to 200-275 degrees and stay fairly consistent in temperature. You can take the internal temperature of the meat while its cooking, instead of waiting a set amount of time. The meat comes out dry, which saves you having to dry it coming out of the bag before you sear.
If you really want to pay to make better bread I suggest you save your money and spend a little time researching designing bread recipes instead. I did and I can recreate almost any bread just by looking at it or by person describing what they want to get. It is not at all difficult once you learn how different processing steps and different ingredient ratios influence the result.
The best investment is to learn how to do it right. Every home that has an oven and a weighing scale has essentially everything that is needed to make artisanal breads.
Of the tools that make life easier but are in no way essential:
The same exact reason you put steak on a hot pan, not cold. If you put it on cold pan it would be cooked through before you get any browning on the outside.
If you take too long baking bread the outside will be dried out, not crisped. Not everybody sees the difference but at least for me it is pretty significant.
Consumer ovens are pitifully underpowered for the most part and will take forever to bring oven to temperature with a large wet mass inside. Even if the oven is preheated the temperature instantly dips very significantly when you put your dough in.
The reason they do it in professional setting is because they don't have time to cool it down and then get it back up to temperature. Another reason is you want repeatable results and not depending on starting temperature.
As to the safety, as long as you are not super clumsy just general common sense is enough to prevent any burns. Don't touch the oven. Use oven mittens. Use extra long mittens if you don't feel safe. Do not operate on the dough while it is inside the oven (tray out, then do whatever you want, tray in). If you use steam to bake (which I do) make sure you understand where the steam goes so you avoid the areas where the hot 200C steam will be when you open oven door so you don't burn your face and hands (the answer: it goes up). Keep your small kids occupied somewhere else so they don't feel the need to have fun with hot oven while baking and after while it is still hot.