No- certainly don't hold the work or vice by hand!
I assume you mean these for using on the lathe.
I have a couple of the V-form drill-pads with Morse taper shanks , and often wondered the same question. I would use tool-maker's clamps to hold the work on the pad. They are shown in old books on using the lathe, but not much more than brief notes on their use.
The V-pad is for drilling across the diameter of a rod, e.g. for split-pin holes. With care the drill should just about break through without cutting the pad itself, but without rigid clamping that is the most likely time for the drill to snatch and pull the work out of control, risking broken drill, damaged work and damaged you.
The flat pad needs protecting by a sacrificial pad between it and the work, unless it has a central hole or recess.
I had to look in Percy Blandford's Metal Turning (published in 1953), and based around using a Myford ML7 or similar) to glean anything about these tools. Essentially I've given it all here as the one thing missing is advice on holding the work or vice safely to the pad. You could use a hand-vice but it would be very awkward and you are still putting yourself rather close to things going round…
Larger work-pieces still within the lathe's capacity could be clamped in a 4-jaw chuck or to the faceplate, with the drill in a tailstock chuck. Balance the assembly it or use it at only low speeds. If you have a vertical slide that gives another option.
It occurs to me the V-pad could be a very useful accessory, if with some way to hold the work properly to it.