Yes it has been used.
It has been effective, but not the terror people on here talk about, because of the range and set up time and spell slot cost.
The campaigns I am currently in are level 5, 7, 8 and 14.
Best you can do at 14 would probably be...
Musician, Human (Alert)
Valor 10(stealth, phantom steed, CME)
warlock 2(chain, blade, Agonizing)
sorcerer 2 (quicken, shield).
With Spell Sniper (Warcaster?) and +2Cha.
Us the familar to scout, pre-cast CME and longstrider on your mount, hide for initiative advantage, and ride in for 7 attack+1 heroic Inspiration nova for 180 DPR (+crits)
Which could one shooting a CR14 about half of the time. Add a little help from an ally (haste, or just damage), and it for sure won't get a turn.
You can still deal a solid dent with level 5 slots
Doing 4 attacks with a level 4 slot = 42 DPR. Not bad but probably better off casting Hypnotic Pattern and EB from the back.