[morzh]

Well,

Sooner or later you will have a hot trimmer. Philcos have a few. So it is better to have one tool rather than two.
Also, however small that could be, there is a capacitance between the shaft and the chassis and it is connected in parallel to your trimmer/padder. It might affect it little or more than that. Considering trimmers are small in the first place, even an extra pF or two can throw the alignment off.

One single wish I have is to have the tool with thin walls so it could fit through smaller openings. I had more than one case where either of two tools (one from Steve, one I bought on eBay from another vendor before) didn't fit through. My hot-formed ball pen tube did, so using a good material of the same thickness it is possible to make an actual slim tool.