Not useless when you can see invisible enemies... which I can. So not sure what to tell you.
Then the RNG was clearly in your favour, but that's
not how See Invisibility is supposed to work. I burned an elixir of see invisibility on a character with expertise in perception at 11th-level and saw
nothing, I had to have my party light the whole room up with fireballs and alchemist's fire to find anything, so that was even
more resources wasted. And even then I somehow missed one who remained hidden after combat ended and then killed an NPC.
RNG is simply
not how See Invisibility works in D&D 5e, it's literally called "See Invisibility" not "Maybe See Something Invisible Eventually if You're Lucky But That's Okay Because it Lasts Beyond the Fight Where You Needed it". I don't know why Larian decided they had to nerf it for no reason, along with a bunch of other spells they've nerfed for no reason like Hypnotic Pattern (which was already massively nerfed due to it being stupidly easy to snap people out of it with bonus action shove, yet they decide it should only last two rounds instead of 10? WTF?)
