I dislike chairs with armrests at the poker table. People scoot forward, or push a chair in, and it bangs the table, disrupting stacks.
I don't need an armrest on a chair. That's why the rail is padded.
Armrests take up more space.
Office chairs are adjustable. So everyone adjusts it to their "perfect" height/angle. Then with a seating change (particularly MTT tournaments) everyone has to readjust their chair for the next minute. It looks like a game of Whack-a-Mole. The Gasser imitation is preset to a height that nearly everyone is comfortable with.
Office chairs allow for fidgety movement. Rocking, twisting, rolling back and forth. This in turn results in bumping the table, bumping your neighbor, and wearing out a small section of your floor.