Note, someone good at math will likely figure out some good math for it regardless.

The thing is that it's not actually hard to do and doesn't actually require any complicated mathematics or proficiency. There are guides out there explaining simple tricks to get it right quickly.

It really boils down to practice - it's fun the first few sessions where it's tricky and the player is figuring it out.

Once you're mid level (and therefore have a ton of d6s to work with) and the player has a lot of practice with it and has read up on the tricks, it's just free power. Literally, free power in exchange for a simple little puzzler. That's really dumb.

It's easy to see for yourself. Say you're level 10, and want to cast a modified 4th level spell. To get 31, one of the numbers on the table, you need a 6, a 5, and a 1. You can know this beforehand!

Once you use the feat for a while, you pick up the easy routes to a couple Prime constants per level. So you are just looking for a 6, a 5, and a 1, right? The odds that you won't get that out of 10d6 is pretty slim, but say you don't. Now you need any combination that will result whichever of those numbers you didn't get, which is trivially easy math. 2 and 3 together let you produce any of them easily, for instance.

Once you realize that you just need to learn a few broken down paths to each number (6,5,1 to 31 for fourth level, 6,6,5,2 for fifth, etc) and have a large enough dice pool that building those component numbers is trivial, adding 2 or 3 meta magic levels to first and second level spells becomes nearly free. This is game ruiningly strong.

It's fine when the player is inexperienced and the dice pool is small enough that failure is a real possibility, but the dice pool increase outscales the difficulty of the problem, plain and simple. Because you can build a number with other numbers, once you have an excess of numbers to play with it's trivially easy to replicate the same basic path almost every time.