"Need" is such a funny word on this forum. If we were reduced to things we actually needed many of us would need to throw out 80% of our supplies.
But my answer is still no, you don't need to have a BBS shave.
But I do. There are many reasons. Pride is certainly one. If I'm going to do something, I'm going to do it well. It's the way I was raised. I like that after quite a long time experimenting I can get a daily BBS with three passes. But it's not a philosophy I'm espousing. Perfectionism can be counter-productive.
So do what makes you happy. I know guys who never break 100 and still enjoy golf. That would not make me happy, but I get it. I'm sure everyone has some aspect of their day where they don't settle for less than their best. Certainly there are more important places for your best than shaving.
I'm still very fresh to the DE shaving game, doing three passes WTG, so obviously I won't be getting BBS and it'll be rough as sandpaper 24 hours later, but the experience of the wet shave is what I'm enjoying most right now. Heck, if I'm not BBS, it means I can look forward to a sooner shave. I still feel great and confident after a shave that I take pride in, regardless of how smooth it is.