On the contrary, I think certain reforms help bring about a proper revolution. The USSR achieved quite a lot, but I don't think they achieved socialism period, largely because of the vanguard. It sounds great in theory to seize total power so you can responsibly divide it without the interference of the bourgeoisie, but historically those with total power are hesitant to give it up. And that process takes time; even if your revolutionary leaders are perfectly trustworthy, by the time power has been cemented they may be replaced by more ambitious leaders (like Stalin, for instance).

In my eyes, organizing and executing a successful revolution is harder than getting a plurality of people to vote in coordination. You'd need that much support for a revolution anyway, so why not try to get as much as we can through reform today while we build the revolution of tomorrow?