that does NOT save you any steps, you still have to perform the workaround steps to get the workaround address as was explained and check if it is correct otherwise all you are doing is deriving a public key and NOT verifying anything whatsoever.

here is the same exact signature with a different message which that site verifies!

so now you have to fetch the address it gives you (18BLXDUbKDiMF34a1dm5hJ3mpCBwsDUowF) and see if it is the correct one while having bc1q7qgn8zw75n26hd60a8ay42482mukdjrdv3cyp7