I'm more interested in if it works than necessarily continuing to do it. It's actually no work however. Why throw something away if making 4 or 5 passes on the curved hone extends the life for another few days?

No holder is required. You just put your thumb on the middle of the blade and slide it back and forth a few times and turn it over and do the same.

These old safety razor hones were sold and I'm assuming were used as well. I'm just curious as to how well they worked.

Maybe it doesn't work with the edge coatings used today?