Participating in testnet this days at your own risk. Although since money isn't involved, one can just risk it out if you don't mind wasting your time on it. The problem here is no one know which testnet will pay so you must try to do all that comes. Since the day of SEI and sui, I hardly partake in testnet. This is because it's time consuming and no one knows if they will eventually pay or not.
Yes its quite risky or unknown or sure income but some of these testnet werent the same with sui and sei that given a different approach on their participants. Im still doing some testnet hopign that it could yield some profits or valuable tokens later on but I know the risk of having no rewards at all unless it got specified by the project.