These are really good points, though holy vision I don't generally use too often because you should always be scouting. Not to say I do this (I often do not) but if you are always scouting properly, holy vision shouldn't be used. But of course it can be helpful regardless of whether or not you are always scouting or not.
There are times where you will simply run into a group of ogres when you try to scout which can get a bit annoying where as holy vision allows you to act more swiftly I find when it comes to expos.
also each paladin that comes out of a rax can automaticly cast one holy vision, so you can check several expos or common temple spots instantly at once everytime you make some paladins, or if you're attacking someones expo and they're sending a group of lusted ogres to deal with you, and you holy vis around the possible entry ways and see them coming , you'll know when to back off and take little to no damage, which is good for annoying them.
It's also great at finding hidden temples and incoming death knights toward your mine, allowing you to either catch it in transit alot easier, or pull your peasants off gold before it hits death and decay.
Heal can also be nice if you're up against alot of guard towers at expansions like 12/2, but it sucks in the middle of a fight against bloodlust