anyone else casting spells at that enermy may find the hex usful if their spell requires a check for example Gale casts Melf's Acid Arrow and hex makes the enermy less chance to make its save for 1/2 damage
Unfortunately, this is not how hex works.
Hex applies debuffs to ability checks, not saving throws. It should not affect enemies' abilities to fail your saving throws.
From the D&D 5e ruleset:
[...]
You place a curse on a creature that you can see within range. Until the spell ends, you deal an extra 1d6 necrotic damage to the target whenever you hit it with an attack. Also, choose one ability when you cast the spell. The target has disadvantage on ability checks made with the chosen ability.
I.e., the enemy would make Perception checks to notice your stealthed characters at disadvantage.
Enemies make
Saving Throws, not ability checks, to
save for 1/2 damage against spells including Melf's Acid Arrow.
I'm not disagreeing with you, just trying to understand. If a saving throw is not an ability, how is that different from perception other than saying it's a saving throw? For example, if Strength was hexed and someone attempted a shove then I would assume by your logic that the athletics would be impacted, yet when I do it in the game, if you view the log I believe (unsure) it says that the target passed it's saving throw (or used to or something similar as I haven't done a shove action in awhile).
As I mentioned in my earlier post, in my play of game combat, using hex does seem to help overcome the resistance to a spell that has that attributes saving throw.
Finally, if hex applied only to things like perception, athletics, mobility etc, why not say it applies to skill checks instead of ability checks and then list abilites? If Hex only applies to skills, it seems to me to be a pretty worthless spell. IMO if you hex an attribute, should it not be effected by anything that uses that attribute including a saving throw?
