This is an expected normalization of html email and the mostly-client-side-apps; Outlook (the desktop app) already renders the html email in a MS rendering engine (Edge? I don't know).
If the email has a button (or a link) - i think it makes sense that the click event shows up "in" the mail client.
I hate html email - but the last 20 years have been all about siloing hypertext apps in email systems - proprietary protocols (exchange, Gmail web - with IMAP/SMTP/pop3 as secondary citizens).
This just a natural continuation.
If you want to escape use a real MUA - and maybe a real mail provider.
Unfortunately if you want groupware - there's no proper open solution (but props to Fastmail for at least trying - but until there are good independent desktop/mobile/console apps with JMAP support - and the equivalent for shared booking and calendar) - it's pretty much either proprietary crapware, or open solutions without feature parity.
I have two Macs running Microsoft Outlook. One is running a version several years behind the current one.
The old machine can send e-mail as plain text. The one running the current Microsoft Outlook doesn't have that option, or a way to enable it that I've been able to find.
I recently changed to macOS, and macOS Outlook is a bit of a puzzle. On one hand an admission that the web app isn't good enough, on the other... It's not quite a proper port of the windows version?
Thankfully i write mostly code and documentation - so far i don't have to care that 2023 Outlook is worse than 2003 Pine.
If the email has a button (or a link) - i think it makes sense that the click event shows up "in" the mail client.
I hate html email - but the last 20 years have been all about siloing hypertext apps in email systems - proprietary protocols (exchange, Gmail web - with IMAP/SMTP/pop3 as secondary citizens).
This just a natural continuation.
If you want to escape use a real MUA - and maybe a real mail provider.
Unfortunately if you want groupware - there's no proper open solution (but props to Fastmail for at least trying - but until there are good independent desktop/mobile/console apps with JMAP support - and the equivalent for shared booking and calendar) - it's pretty much either proprietary crapware, or open solutions without feature parity.