If you're doing all of the emulation and signal processing on a general-purpose computer, then sure, you often run into latency problems, and part of the set up process for those software tools is latency calibration. The one that I use when at my desktop, Guitarix, is very conservative with its latency, defaulting to like 500 milliseconds, I turn it down to 20-30 or so and it still functions on my hardware and you can't tell the difference: it's the same time delay as playing through a speaker 20 feet away.
If you're doing all of the emulation and signal processing on a general-purpose computer, then sure, you often run into latency problems, and part of the set up process for those software tools is latency calibration. The one that I use when at my desktop, Guitarix, is very conservative with its latency, defaulting to like 500 milliseconds, I turn it down to 20-30 or so and it still functions on my hardware and you can't tell the difference: it's the same time delay as playing through a speaker 20 feet away.