Yeah, part of an application might be CRUDing big pieces of structured data, and for that I think jsonb is the best compromise (https://news.ycombinator.com/threads?id=hot_gril#37123355). Comes with the limitation that you can't have FKs into the objects, but you shouldn't anyway.
It's hard to be sure that CRUD is all you need. Maybe you'll be fine, maybe you'll get stuck between keeping a slow DB or rewriting everything (I've seen this movie several times). It doesn't cost much to go proper relational from the start, especially cause that involves the least tooling/boilerplate. And if you're really sure you only want objects, NoSQL DBMSes are actually designed for that.
It's hard to be sure that CRUD is all you need. Maybe you'll be fine, maybe you'll get stuck between keeping a slow DB or rewriting everything (I've seen this movie several times). It doesn't cost much to go proper relational from the start, especially cause that involves the least tooling/boilerplate. And if you're really sure you only want objects, NoSQL DBMSes are actually designed for that.