Yep, very useful bit of kit for spring/autumn riding, they’re a constant fixture in my commuter attire from about now until it gets properly cold. I’ve got a pair PX merino wool which are very good but prefer an old, cheap ASSOS pair for when it’s wet. Knee warmer are also a useful bit of kit for similar reasons.
And don’t forget to add more time when getting dressed for a commute as if your good lady/man walks in on you wearing the striking combo of nothing but knee warmers, arm warmers, HRM and socks they may not be able to contain themselves…