Transactional email is definitely required for developers to ensure email deliverability and flexibility. Digitalocean can provide free tier to those email triggered from droplet (just like there is free tier in AWS SES for emails triggered from EC2) this would encourage developers to spin new droplets as EC2 is tad costlier than Digitalocean. Maybe you can offer around 15k-20k emails free per month if triggered from DO droplet. You can also have different tiers for different droplets .. just a thought. Those is favour please vote.