I think that everyone still converts what-ever-unit used to time. For example, from one of my earlier jobs, we had "T-shirt"-size units, ranging from XS to XL.

I think that everyone still converts what-ever-unit used to time. For example, from one of my earlier jobs, we had "T-shirt"-size units, ranging from XS to XL. It took two weeks after introducing them until someone figured out that XS is two hours, so in a sprint you should be able to do $SPRINT_DURATION / 2 XS tasks. And then the person figured that S was equal to, say 4 hours and so on and we were back on square one. But we didn't estimate in concrete time units. /s