Less tab clutter, enhanced ability to use OS app/window management facilities, no space eating browser chrome, works without a browser being open (yes that does

Less tab clutter, enhanced ability to use OS app/window management facilities, no space eating browser chrome, works without a browser being open (yes that does happen on occasion). It doesn’t apply to Proton’s desktop app specifically but generic email clients also allow management of multiple accounts in a single window without the messiness of forwarding.