As mentioned elsewhere in this thread, simple CRUD usually stops being simple CRUD pretty quickly.
If you are actually doing simple CRUD, then DRF's ModelViewSets are great, and Pydantic would indeed be an overkill. However once the view diverges from your DB model, writing Pydantic models IMO is FAR superior than having to write custom DRF serializers.
DRF is very dynamic. While useful, it does too much magic for my taste. Pydantic pure data models, combined with typeguard annotations do it for me. Plain functions with defined input output types. It helps validate all the assumptions and catch errors earlier.
OTOH, if you're a big fan of NoSQL databases, then pydantic is a godsend.