I too made the mistake of doing amount*0.05 when they provided me the pricing in beta.
This is why I went with them, if I can't do a simple percentage computation I'd rather not do the taxes myself.
And if you're making $1M a year, it will then be $4,000. And I guess that's still cheaper than having your accountant going through all your Stripe documents, computing taxes while also, on your side, having to make sure you're 100% tax compliant. Maybe at $10,000,000 it will start being a bit pricey, but at that point you'll most probably discuss with Stripe to reduce that fee.