Dynamic IPs are not a problem for torrents. As for NAT: Many routers support PCP or UPnP IGD which lets the torrent client open the port. µTP can also exploit from simple UDP hole punching to allow incoming connections if the NAT is full cone (alas, iptables' MASQUERADE is not, despite IETF recommendations).
What you say is correct, but note that I was talking about direct connection to a specific person.
BT is great for "giving out to the world", but if you want to send a file to a friend, using an email, a cloud drive link or Skype/whatever is more practical. Intermediary storage is required for asynchronous transmission, and even if both you and your friend are online, you still need to take an extra steps of creating the metainfo file and sending it or a magnet link first and then wait for the DHT announce and lookup procedures to execute, which can take quite some time.
Yeah, at best it would be for technical users, and even then for 1:1 sharing a streamlined client tailored to that usecase would probably help. E.g. various status indicators that show whether nat traveral/hole punching is possible, discovery of the public IP address to include it in the magnet link (the x.pe extension!) to skip the DHT lookup if possible and a less complex UI. If you do 1:1 transfer you don't really care about your share ratio for example.
Even using public trackers (in addition to DHT) I haven't had any luck trying to send friends my torrents. They just never discover my seed, even though I'm conectable. It's very odd.
If you are connectable you should set up your own tracker.
Even the old python-based bittorrent command line utilities will work for this and it's a piece of cake to get going.
So whether it works depends on more circumstances