Nobody is saying that you should play CE with the intention of deploying. But there have been loads of times when I've logged into a round and seen that there are: 2 squad engineers, 1 of whom is a Delta that spent all of his points on claymores and is offended by the very concept of building things while the other has absolutely no idea what they are supposed to be doing and will either fail to deploy or die without building a single cade. 0 MTs(or one who has either gotten arrested or gone AFK within minutes), no synth, but there's a CE who has a good enough idea of what to do. So, prior to this point, sending the CE down made perfect sense and resulted in a round that wasn't a complete joke for everyone involved. Not sending them down has the same result as if they didn't exist: no defences are built and the round ends up as basically a waste of time because at some point a xeno notices that there's no FOB and the entire hive casually wanders over and seizes the LZ and kills everyone. Both versions of this scenario have happened to me many, many times, because I play low-pop. This is the issue with such a ruling: in a high pop round where all the departments are well-populated and all the squad roles are represented well, and there's probably a synth, sure, it would rarely be an absolute necessity to send down a department head(although I do not think it's at all unreasonable to let them help out with something around the FOB, firmly away from the actual front, if they're otherwise just loafing around the ship or there's a desperate need of manpower). But when the department consists of one guy, and there are holes in the groundside composition that desperately need filling, saying "nope, they can't go do that" is a big problem, and I feel like it's an incredibly heavy-handed response to the occasional problem of department heads running off to shoot xenos(which you could very easily rule against with "only deploy if there's something that's firmly within your area of expertise that needs doing on the surface" instead of just "never ever").