It'd be awesome if it wasn't just random letters and numbers with no apparent meaning at all. You can graffiti flowers, spaceships, and Sunsets, too, right? This is the art equivalent of an accountant in a monotone voice reading off a long list of names nobody cares about.
Except that it isn't random numbers and letters, this is the artists tag names, they're laying claim to each piece.
I get what you mean about making it beautiful, but these are probably just basic taggers incapable of that level of artistry, they're probably just a bunch of delinquent kids, plus a balcony wall doesn't exactly give you a lot of canvas space, especially with a spray can.