that's not the only feature of v2. it also hels a lot with swarm merging (which with v1 only biglybt implemented), and it has updatable torrents. it also stores torrent information more efficiently and the incoming pidces can be verified immediately. afaik today torrent clients don't verify downloaded torrents by default. qbittorent has an option, default off, to verify after a torrent completed. this is slow because everything needs to be read again from disk. I'm not totally sure about this, but I think a malicious peer could be sending crafted pieces that contain something else and you wouldn't know it.

https://torrentfreak.com/libtorrent-adds-support-for-bittorrent-v2-a-potential-game-changer-200912/