I would say wise practice....
I do it when single handing and when my son is on the boat, he is also tethered... it is a PITA but!!
It is nothing fancy... just some 1/4" line with a caribiner at each end for the foot-strap and around the harness metal spreader... To my good fortune I have never had to employ it...
And this too.....
I never get onto a boat without a VHF tied to me.
A radio (or cell phone) on the boat is completely useless if you're separated. And (even if equipped with a tether) you should plan to be separated...
Mike