If you're fine with using euros/SEPA, you can avoid Etana. If you want to withdraw or deposit dollars or do international transfers, you have to use this "custody". I checked their introductionary questionnaire, it is ridiculous. They want to know information not even my mom knows.
Also don't expect Etana to function as a workaround if your bank doesn't like Kraken. They will figure out pretty fast what Etana means and if they block Kraken for whatever reason, they'll block Etana sooner or later. It is a depressing world.