No, Workers free tier is 100,000 requests/day. Considering the error is on the main page, each visit is probably taking a minimum of 10+ requests, so it can easily be overwhelmed.
No, the paid plan scales to infinity (without having to beg for limit increases like on some other clouds). But ther paid plan has a $5/month base fee, so it's tempting to stay in the free plan if you don't expect to go viral
