A: Hi,

It's Alex the founder of ProxiedMail.
Thank you for the question.
We have more features: custom domains, built-in password manager, API, custom email bots.
Also we don't own any email client, so we don't have any conflict of interest - we would never force you to use our email client.
We're just the emailing tool, while Apple has their own interest to tie you up to their own system.