Don’t know what you mean by based. Yes, same banks are backing WERO as iDEAL. WERO site explicitly says it’s new infrastructure and they are migrating, not upgrading.

But it’s also has nothing to do with WERO vs BLIK. WERO-backing banks don’t give a shit about Poland’s users. Or they simply do not operate in Poland. Say ING, they operate in Poland since 1988 but didn’t manage to rollout neither iDEAL nor WERO. Moreover Polish branch of ING supports BLIK. I don’t know why they cut off Polish users from WERO.

I’m pretty sure both BLIK and WERO banks would like to keep tech for themselves for sometime to make it selling point against competitors on local markets.