I find items like the Circlet are most useful to bump up a character's secondary/tertiary stat (i.e. INT for eldritch knights or arcane tricksters, among others) until they are able to raise it up on their own through ASIs. It doesn't make any sense on a character whose primary stat you want to get to 20 anyway.

I haven't seen a ton of interesting headwear in 5e, not that some doesn't exist and more can't be homebrewed. The real cost of the Circlet is that it eats up a precious attunement slot, and there are so many better things you want to use that slot for down the line. It's a decent first attunement item, but you're generally going to want to replace it before too long.