I had to install the app to try and work around a problem with Steam, and then had the same problems just browsing. You can probably disable that behavior, but I ended up just uninstalling the app entirely.
The support experience was so bad that I got really soured on Valve, and can't even get excited for these announcements now.
Forcing the use of the steam app for 2FA is such an ass move. Keeping this as a reminder of Valve still being a corporation with interests that can shift to the worst in a single day.