I have the Boots of Aid and Comfort. The description does not say what they actually do. I used Astarion (fewer powers), took off everything he was wearing, checked his status screen, then put on the boots and checked his status screen again. No changes were apparent. Did I miss something? Help?
We don't know yet. Been trying to figure this out for weeks.
They don't affect difficult terrain. They don't confer ability changes. They don't add an ability.
They don't prevent lethargy.
To be honest I am not a fan of this sort of mechanic. There are spells in D&D 5e which would Identify (called Identify btw) that would tell you what this item does but since we don't have those spells we just have to guess. And so far nobody knows.
They could be unfinished or bugged. Or maybe they only affect a certain class or origin character.