Sadly, the microtransaction concept has gotten a bad wrap over the years. There are always those that will abuse the system, and as pointed out, will nickel and dime players.
On the other hand, there are simply players that would rather fork over a buck or two here and there for cosmetic upgrades, double xp for a limited time, etc. At the end of the day, I think it boils down to choice. Some would chose to use microtransactions, others not. It doesn't mean that one is 'better' or has advantages over the other...it's just a matter of personal preferences. And at the end of the day, wouldn't you rather have a choice than no choice at all?