At my work facility it would take more time to use the shower facilities than to do a sink shampoo/bathroom stall scrub.
It is almost a mile walk inside the factory building between my desk and the showers, and an extra trip back to get the bike.
I have a long commute and simply don't have extra minutes to use walking around the facility.
I've commuted to another site that didn't have showers, and found the birdbath was perfect despite arriving in a sticky gritty sweaty mess.
The restrooms I used were within a minute of my desk, so I could stash toiletries and towels at my desk rather than carrying them on the bike each day.