why we can't do this ?

Hi,
I was wondering why it was impossible to do a procedure:

If: [is (block here) = (stone) or (dirt)]

but only:
if: [is (block here) = (stone)]
or: [is (block here) = (dirt)]

Doesn't it slow down the game to always look for the block at xyz when you can keep xyz in memory if you have 10 blocks that you want to choose without wanting to make a useful tag in a single situation?

Sorry if this is in the wrong place I just wanted to know and no other forum seems correct