There are a number of policies and rules that make such an extension difficult. You can’t monetise non amazon transaction objects, and the whole point of this extension would be to send them offside to go do the thing.
So if it’s ok by the rules you still have the transaction problem, and confusing user UI since it would just be easier to start offsite to begin with.
There is also a promotion problem, (I had issues just linking to a GOG List of games for example)
See 4.5, 4.6.3
So this just works better as a panel button/link to an offsite thing rather than an extension.