alt Hacker NewsYes, that was my first thought. It's wild to me that GMail would support sending as yahoo.com, outlook.com, etc. in the first place. Google makes lots of questionable decisions and shuts down lots of products uncessarily, but this is not a strange or unwarranted move.
It's not wild at all. It's just behaving like any other MUA but with an extra step. You have to give GMail your SMTP submission credentials for the sending server of the target domain, then prove ownership of the specific address you want to send as. SPF/DKIM/DMARC works fine, as GMail is just submitting your message on your behalf the way any MUA would.