They're the same GPU as the R9 280x - not great ETH cards but will work, fairly good ZEC cards.
If your electric cost is low enough they should be solidly profitable.
The amount of VRAM has no effect on the memory controller "thrashing" issue - but the wider memory BUS makes them less effected by it as well, even without the "blockchain" drivers.
They also have a great future as workers in the BOINC "Milkyway" project (and can earn decent GRC that way) since they have very high FP64 performance for a non-workstation-specific card.
Where are you getting these for $50/card?
??