Advantages of the VB:
-8 tracks (Teletype can only do 4 internal patterns)
-Slider-based programming interface
-CV mode, where you can lookup voltages from a CV input instead of clocking the unit.
-Very quick and easy quantization. The TXo adds quicker per-output quantization to TT, though, which is great.
-Ability to turn on smoothing per-step (This could be done somewhat with TT and SLEW, but would be rather complicated to target only specific steps per pattern)
Advantages of the Teletype emulating something like VB:
-Each track is completely independently clockable. On the VB, you can add per-track clock division, but that's about it.
-More steps (up to 64 in a pattern, I think. VB has 16).
-Wider voltage range
The closest Monome analog to Voltage Block is Kria with its "one clock driving phasing patterns" concept.