I think that’s appalling frankly! Not least of all because companies should, at the very least, be able to identify that you’re making use of that gmail feature!
Can’t say it’s an issue I ever ran into with Bulb though, though any email communication would always begin with me replying to an email they had sent to me, and I guess they just didn’t bother to check the email the reply came from.
Email spoofing is far too common, and far too easy to pull off, that companies really shouldn’t rely on this stuff. All it takes is a data breach. And if I used my personal email for everything, fraudsters would be able to acquire enough information about me to not only spoof my email, but impersonate me and use other aspects of my identity to get through authentication too.