I'd say GPMC is in contraction mode. First AXS payments were stopped, then you couldn't use it to pay for lots of things, then they devalued the Grab rewards, then they added lots of exclusions and finally every credit card stopped giving rewards when funding GPMC.
I imagine when GPMC first came out they saw a huge increase in volume but now what's the point of using it? It's not like anywhere only accepts GPMC. I know I don't use it anymore.
Think it is more of them cutting loss.
