In non-video form:
The Prophet X's sequencer is polyphonic with up to 6 notes triggered per step, so it can absolutely fill that role. There are indeed several factory sample sets that are conventional and electronic drum kits, laid out with different samples on each key. Better yet, individual keys can have multiple samples assigned so that when the same instrument is played over and over you can have some variety. This is referred to as a "round robin" collection of samples, and it's in addition to being able to have different samples for different velocity levels.
The drawbacks to using the Prophet X as a drum machine as I see it:
Until we get user sample support there's no way to customize what sounds are arrayed across the keyboard in a given "kit." The combination of sound is a pre-determined part of a sample group. There are usually a few different snares and kicks in a single kit to offer some variety, but they've been pre-selected as likely to work together which may or may not meet your needs. User sample support will make it possible to arrange any externally provided samples the way you want with external software, but it won't help rearrange the factory samples (unless you record them and re-import them, I guess.)
The synthesis parameters on the Prophet X are ideal for an instrument that stretches across the keyboard, not one that has unrelated sounds on different keys. Want to pitch just the snare up? Tough. Want to apply a nice envelope-defined filter to the toms? Great ... if you don't mind it being applied to every other drum in the kit as well.
The Prophet X will work as a source of drum sounds and can be a great complement for an existing drum source, but it wasn't really designed as a drum machine. Keep that in mind and you can certainly get some great use out of it. The Super Plate reverb is amazing with percussive sounds and there are plenty of wonderful drums in the factory sample sets.