They convert arbitrary storm counts into damage, which usually wins more reliably than something like Brain Freeze or Ignite Memories
Speaking of running the numbers, a good way to do so is to use a hypergeometric calculator
While this is certainly easier to do in 4 color partner builds or 5 color decks, as those mana bases usually need to lean almost exclusively on basic lands to ensure consistent access to all colors, there are more than enough nonbasic lands out there at this point that you could play this instant speed tutor in any deck containing black
The most common Trainer cards are items, tools, supporters and stadiums
And theres another mechanic that plays into the sanity of the characters
Im specifically thinking of Liberty Prime, Recharged, since you can proliferate both energy counters and the charge counters on Inspirit, and a fully stationed spacecraft would also protect Liberty Prime and other artifacts you have