It doesn't really matter. In practive it's only usable as minor rain protection anyway. I'm not bringing my phone into the shower. And like people have mention

It doesn't really matter. In practive it's only usable as minor rain protection anyway. I'm not bringing my phone into the shower. And like people have mentioned, the most rugged phones do have replaceable batteries. I used to have an Xcover for hiking and it never had any issues with water ingress either.