Despite having ROMs, I like having "official" versions when they are made available. Mega Man Anniversary Collection is a good example where, despite having ROMs, I consider the purchase money well-spent. Emulation was spot-on in that collection, plus you had a nice interface and some extras.
I won't be getting MAT2 though, because of all the flaws. If I did buy it I would never play it; I'd prefer the less glitchy version that lets me play online (MAME + Kaillera).
If this collection was bug-free and had online play, I would have been all over it. I would gladly pay $50 for that.