There's also a reason that the "legitimate nerds" in show business become such cult favorites. The overlap of (1) "people who look like professional actors" and (2) "people who are believable while acting" and (3) "people who legitimately get into the fake logic of technobabble" is vanishingly small. If you are on a Trek show and not in that intersection, pretending to be a 3 is going to be one of the biggest challenges in pulling off 2 to your expected standards.

To cross franchises for a moment, "you can write this shit George, but you can't say it."