A fun way I've been using the presets since it's been added in .12 is by naming the guns I steal from players with their in-game name. It acts as a trophy and I can go through my presets and see my library of kills as a fun reminder and go back and build those weapons even after I've lost/modded them.
I just thought it was an interesting way to use the presets and every friend I've told hadn't thought of it but said it was a good idea so I thought I'd post it here.
Source: https://www.reddit.com/r/EscapefromTarkov/comments/e126x7/using_presets_to_name_stolen_guns/