As someone who has a noncommercial side project and has been using SendGrid's free 100/day plan, I'm actually thinking of switching to this. I've always been a bit concerned with what would happen if my app got a sudden burst of signups (since email verification is required to sign up), and have been looking for an uncapped plan, but don't want to spend $10 a month or more just for that possibility.
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.
I run a gitlab for around 30 users and that’s around what I use on AWS to send my emails. It’s a bunch. Rarely do I send emails on weekends so it’s like 20 days a month I send emails just for merge requests and stuff.
Hobbyist to me means that you are doing it for fun and aren't engaging more than 5-10 people. So given that, I'm having a hard time understanding how 10 people could handle 625 emails a month.