Some characters might not want to use the Headband at all, even if it was a full Headband of Intellect, which should put the Int value to 19, not 18. Especially not in BG3, where they have imported one of the old school rules; some helmets negate the critical damage bonus or carry other benefits.

This being a Mindflayer story, however, it will definitely see a lot of use in my parties to help with Int saves and make it less likely Intellect Devourers 2 shot my characters.

Don't you just hate it when people with dumb opinions have nice avatars?