One example would be state disability programs, they already need my real name and identity to work with me. Are there any downsides to sharing a simplelogin alias containing my real name vs no containing my real name? I just think it would be easier record keeping for them.
Not really. I’d still use separate aliases for each organization with a random suffix in SimpleLogin.
There shouldnt be any issue because they already know. Besides if the body of the email isnt E2EE encrypted (as in Protonmail ← → GMail), it is best to treat it as a public social media post. If you had to submit a file that has your sensitive/personal information, consider encrypting it and sending the password using an alternative method, even if it is via SMS/FB Messenger/WhatsApp at least there is some sort of compartmentalization of information.
I’ve had some companies complain that I’ve used their name in my email aliases.