Actually, some are clickie spell effects. However with this particular piece your right, it is a worn effect and doesn't take a spell slot. I do not know if this effect stacks with FT15, thus giving FT18, or if it counts towards the FT15 limit.
What is the difference between a worn effect, such as "Composure," and the same effects separately, i.e., Mana Regen 3 and Regen 3? Does it make a difference that it is a focus-effect type of thing as opposed to two separate "regular" effects? Basically, I want to know if this effect "dodges" the FT max cap.
Composure is -exactly- the same as Mana Regen 3 + Regen 3. A while ago, Sony removed all effects like "composure" from items and replaced them with hard regen/Mana regen numbers. They basically made an error and put an old, out of date effect on this mask, and I believe it has since been changed to just have Regen3 and Mana Regen 3.