I think 10000 was probably too generous, but 625 also seems a bit too little as well for hobbyists.
The key here is that with the $0.80/1000 emails PAYG rate, you can still do like 2000-3000 a month for less than $5, which no one except SES will provide. Everyone else has a gulf between "free tier 100/day" (or even 100/month with Postmark) and their first actual paid tier ($10/month for Postmark, $15/month for SendGrid). No one else except SES has this PAYG for low rates as far as I'm aware. I think if your hobby project needs more than 625 emails a month, it's reasonable to spend a dollar or two on a month to handle that.