There’s not a lot of use bidding for upgrades today for most folks, though remaining Air Canada flights if you’re traveling may have seats available. In the future this will be a more useful feature.
Selling miles makes a ton of sense and it’s really strange that it wasn’t something Aeroplan had done. It doesn’t make any sense buying at regular price. What Air Canada – and every other airline – should be doing now is offering miles for sale at a deep discount.