Registering to be an expert has lots of value – you could get paid to evaluate and monitor projects or evaluate calls for proposals under the schemes. Indeed, becoming an EC evaluator is a fantastic experience; it not only helps you learn what the EC are looking for in proposals, but also enables you to travel to Brussels and network with other reviewers to start forming collaborations yourself.
It’s really simple to sign up, you just pop your details in the form (which isn’t very long) and when an appropriate call or proposal comes up, they will ask if you can review it. If you can’t, you simply let them know and you are not obliged to. You also get until December 2020 to sign up to be a reviewer if you aren’t quite ready yet!
You will get paid a day rate to do the review plus travel and subsistence and you can also still apply for the funding scheme if you are registered as a reviewer (although for a specific call you apply to, you would have to declare a conflict of interest).
More info can be found here