If people are displaying LN invoices as a means to receive payment, there should not be a major de-anonymization issue, as it is not trivial to get a lot of information about transaction history from a LN invoice, and is even more difficult if you are not actively monitoring a channel.
Assuming that they are only going to allow you display Lightning invoices. I'd be very surprised if there was no option to display a standard Bitcoin address, especially if the information about allowing users to display Ethereum addresses is accurate.
When Twitter was hacked last year, they prevented users (it might have only been verified users) from tweeting anything with a bitcoin address. Displaying a bitcoin address gives you the same amount of privacy as posting an address here. Tweets are generally not indexed by search engines, so tweeting an address might give slightly more privacy than posting one here. Displaying an address in your profile probably gives about the same amount of privacy as having an address on your profile here.
It has the potential to be even worse than what you describe. Accounts can get hijacked, and new addresses/invoices can be changed in a profile without someone creating even a single fraudulent tweet.
I never even thought of that. How often will the average Twitter user visit their own profile to double check the address/invoice hasn't been changed. Even worse considering a hacker could have days to generate a look-alike address using a vanity generator so it is not immediately obvious.
Most people don’t tweet every day, so even if you checked to ensure your address/invoice has not changed every time you visit Twitter, it could still be changed for days.
One solution might be to make changing an address to be a “security event” which results in an email being sent to the user and/or requiring a delay before the changes address/invoice is displayed.
