I have seen a number of these conversions. Mostly, the conversion is made by technicians because they want a more service-friendly action. While that is an argument, it should never be a deciding factor above action performance.I have yet to see an action where the oh-so-dreaded rocker capstans were replaced, that played better than before. Many play really badly.
Rocker capstans are not that bad, you just have to know how to deal with them and have the right tool.And, when working on vintage pianos, it helps to have some respect for the designers and builders of these actions.Always.