In the U.S., to interact with a bank, Strike requires KYC with the data harvesting organization PLAID. i.e., you must give Plaid permission to rifle through your bank account history, and to keep doing so further whenever they wish to.

So I only use Cash App with my bank account.

If I need to convert BTC to USD into my bank, Cash App is the quickest, most convenient. Not the least expensive, but for small amounts that's OK.

But when I go to transfer from Stacker.News, for instance, to Cash App, I cannot (Issue #1109).

But Strike can. So I can deposit LN to Strike, then from Strike send to the Cash App LN invoice.

Other differences between Strike and Cash App. With Cash App I have a debit card. I can deposit BTC (via LN even) and have the proceeds immediately available for spending on the debit card.