I hate when players absolutely refuse to do any minmaxing. It ruins immersion when you aren't any good at what you are supposed to be good at and most players will naturally minmax to some extent, so a poorly designed character kind of sticks out. That's in a TTRPG.
In a CRPG, I only wonder why anyone would find it interesting to not minmax. I mean, I played a low INT Wizard in a playthrough, but even then I made sure to build something that would work (Shield Dwarf); that was actually a really effective character. You'll barely notice if your Fighter has a 12 INT instead of 8, but if you pulled those points out of STR or CON, you will feel that. I'd rather just toggle difficulty higher and build a good Fighter. It matters less if you are playing alone, but in BG3 you are leading a group of NPCs and are going to do amazing things; you should be first among your peers.
That said, when playing in a group, I don't like the kind of minmaxing that relies on rule quirks to do 10,000 hp damage per round. That's more like exploitation of the rules. Every player should feel like they are contributing the story in an equivalent (obviously not "equal") manner.
It depends on what's being defined as min-maxing. You are correct that if a wizard can't do wizard things well or a fighter can't fight very well then what's the point? In my case, what I mean by NOT min-maxing is that while I will try to 'max' the key stat (or two) for my character. I won't tank my other 'non-essential' stats. So, I will rarely ever make a stat lower than 10 in any PC that I create (and never lower than 8). And if that means I have to settle for a 16 or 17 for my main stat, so be it. Typically I'll still have an 18 in my main stat, and have to settle for a 15 or so in my second-main stat. This is NOT min-maxing to me.