Im messing around with spriest for the first time ever and am a total newbie to the spec but im trying to figure out if I need it on my bars since Vampiric Touch applies it in ST and Shadow Crash does in AOE and then it shares a duration with VT so there’s no desync there like there is with boomkins dots.
It’s used when you are moving and have literally nothing else to use. You can look at logs for top shadow priests and they are often not using it at all and when they do it’s only 1 or 2 times per fight.
So, no, you don’t need it on your bars.
For pve, no not really
No, you don’t need it on your bars.
As long as you have the Misery Talent (which is all but mandatory) you don’t need to have SW: Pain on your bars
No idea about pve but for PvP you would want it for certain scenarios like trying to keep a rogue out of stealth before he goes around a pillar, etc.
In PVP you can get people instantly into combat and you can also destroy low hp shaman totems (do they still have like 5 hp?)
In PVE (M+) I use it mostly when the group is running a longer distance with a pack of mobs and I just apply sw:p on the run until we stop and I can start casting (beginning of theatre of pain ghost wing).
There is the synergistic brewtalizer trinket as well where you can use a macro to auto-target and kill it with sw:p’s instant damage. That is an absolutely horrendous trinket in my opinion but for that sw:p is the perfect tool. ^^
Definitely good for old content though, it’s always on my bars for that.