There's quite a bit of research going into miniature thrusters, which will be very useful for heavily miniaturized probes. Of course, nothing stops us from using these thrusters on larger probes (if you need bigger payloads), and they'd likely be more efficient in that case. It's all about mass ratios and specific impulse, also known as the tyranny of the rocket equation. 100 m/s from a 2x10x10 cm system is quite respectable. Let's take a look at the claim about being able to reach lunar orbit with 6U worth of these (30 systems). You need around 4000 m/s to get from LEO to LLO, or at least 40 of these systems. But this is with having multiple sets of thrusters and not simply having multiple sets of fuel tanks that you jettison along the way. So I recon it's possible, but would likely be tricky due to the low thrust. Perhaps some kind of low-energy transfer could help, like what was done with PAS-22.