Flying fairly frequently with *A, plusgrade is something I am familiar with and have benefitted from some upgrades.

It is likely to reduce the frequency of op ups as these will get sold to people who put in the smallest bids on the off chance they might get lucky.

However OpUps may occasionally still be available, especially on Short Haul connecting flights. People will bid for the low upgrade on the long haul but less so for a 1 hour connecting flight