The big issue still is that counting such big numbers does in fact takes a bigger toll on server hardware than smaller ones; It is different is a server needs to calculate from 34567890 hp when you deal 1234 damage or from 23832008239189432973 hp when you deal 3493292343 damage. Also as you see at this point, numbers get simply too ridiculous; just think what this look like in a combat text. Yes, Squish was necessary after MoP; but blizzard does it in fact far too often now. That's because numbers inflates far too fast in this game right now.