Formula columns are great, just read Work with Dataverse formula columns. But there are some limitations in the Power Fx functions you can use, as well as with the return types..

• Need a formula column returning a whole number? Make it a decimal with 0 precision.
• Need to produce currency? Make a formula to return a decimal, then convert it to currency using the good old calculated column where you can define the return data type instead of inferring.
• Need a choice? Your choice can only be either yes or no. But the same trick applies. Do your magic in a formula column, then create a calculated column and go through the painful if-then-else process ad nauseam to cover all possible return values. To be honest, I’d rather eat a frog and write a plugin.

Personally, I think it’s all because, ironically, Power Fx in formula columns does not support Power function. Source: trust me, dude.