PayPal ID used for contribution, only email address?

Hello.
It is a column of “What is your PayPal ID?” In the item “Manage Payments”.
I’d like to set up a merchant ID, but apparently I only accept email.

The error message is "The email or merchant ID specified is invalid."
I hope to be able to use the merchant ID to prevent spam from coming.
After entering an invalid email address to confirm, it seems that it is done only judging whether it is a mail address because it was able to save without any problem.

Yes, as far as I know we only support an email address for the Paypal ID field. But I also think that the email address isn’t exposed to the user in any way. Can you explain what your concern is?

I configured and confirm the email address of my PayPal account. It was not found on the page.
It’s a good implementation.

Let’s change direction a little.
Since the form and error message does not match the implementation, I feel that it is better to modify one of them.

Fix message. This will be changeable at a lower cost.
Change part of the implementation. Instead of taking a bit of effort, you can also deal with merchant ID.

I would like to support the freedom that developers can choose the options that are prepared at the cooperation destination.
I vote for implementation changes.

Withholding display of personal information is most preferable. Now if only there was an easier way to donate via paypal without compromising my real world identity. There is a way, I do it now, but this is not the place to re-educate.

Please also see this topic.
Upcoming changes to Contributions on AMO