There's no need to seek compounders, as rewards are distributed weekly, you don't really gain anything extra, you can manually compound yourself by doing a single asset deposit into a pool each week if that's what you want to do: this takes no time at all.
With third-party apps offering amazing interests, you're risking losing your tokens & rewards, and remember: Balancer has no official affiliation with any of them! So if they steal your BPTs or rewards, there's no way Balancer can help.
We want you to be informed, please do your own research before investing. The safest way to compound with Balancer is to compound yourself each week. If rewards were continually streamed, there would be some marginal benefit to a compounder, but even then, opportunity cost might not be in your favour.