Maxperson
Morkus from Orkus
...but it does remove the key balancing element of random scores.
I totally get that most people use random scores because they want to be "surprised" by the character they get. That's fine, perfectly cromulent. The problem comes in when we start rejecting only specific kinds of rolls.
There's no problem at all, really. The difference stats make is really minor and doesn't have to be balanced. If the little bit of balance differential is a problem for you, either don't roll at all, or don't allow re-rolls.
So no, it's not "cheating" in the sense of "secretly violating a rule." But it is "cheating" in the sense of "milking the system for an unfair advantage." Plying your DM's heartstrings to remove the balancing effect that's supposed--mathematically--to keep rolling from being completely superior to point-buy.
Would you prefer the term "exploitative"?
It's neither "milking the system", nor "exploitative." It can't be since the DM has changed the rules to allow it.