Tell HN: Stop using Apple's Hide My Email, its a one-way street
Since Apple has done the marketing as such that with a click of a button, it will create a unique email address for any business you want to sign up with, I doubt many would think twice because its all so simple and Apple way of a solution, sure, why not, let's use HME everywhere to protect your privacy and if you feel the business is not respecting your preferences, you settle out any bills with them and deactivate the email address given to them.
But what if you are working with a business with strict email policy and no other way to contact them, how do you file a ticket with them? How do you email them?
Let me point you to this support article where Apple still doesn't point out the glaring truth of HME that you simply cannot send an email with a previously generated email address
https://support.apple.com/en-in/guide/icloud/mm9d9012c9e8/icloud
When you use HME on a website (for e.g. business.com), you can check on your Mac that the HME generated for the website, on the top it will say Safari and in the label will be the domain name of the business(business.com). Let's call the email generated by HME as hme-1@icloud.com.
Now if you were to use the Mac app or iCloud Mail to compose a message to support@business.com and choose HME as the sender, it will not populate hme-1@icloud.com, it will be just another random address like hme-99@icloud.com. It does not take into account that since hme-1@icloud.com has been assigned/mapped to business.com, the Apple user should technically be able to send email to any email address of business.com like admin@business.com or techsupport@business.com or sales@business.com.
It would have made sense for Apple to say, if the Apple user was trying to send an email to sales@sales.business.com, of course we won't let you send that email because the sales user belongs to sales.business.com domain, not business.com domain for which we have assigned hme-1@icloud.com to you.
I tried to explain this fundamental thing to Apple's customer support that emails are a two-way street. Just as how I am able to receive emails from any@business.com, I should also be able to send email to any@business.com.
But according to Apple, this design is as-intended.