Except when it’s not. Like when trying to square a glued-up panel that is too large for your shooting board.
No purest am I. I’ll use whatever tool makes the most sense under the circumstances. In my opinion, nothing beats a carpenter’s square, straight-edge clamp, trim router and flush trim router bit for squaring end-grain on a large panel.
Give it a try. There is a reason my trim router (and dust extraction unit) has survived every power-tool purge in my shop thus far.