I am so glad people are finally noticing and complaining about this. It's the same reason I won't use Spark or Superhuman. Those are neat services, but I can't abide storing the creds to perhaps the most security-sensitive service I use to a cloud provider. If they get hacked, then the attacker can access my email account, send phishing emails to my contacts, read and respond to password reset requests they make to other online services, etc. It would be disastrous.

No, I'll keep my credentials stored and used locally, thanks.