Hand-to-hand is also pretty useful because, you know, ships hallways are pretty cramped and you could easily be staring at the boarder's nostril hair as you turn around the corner.
I have a pair of brothers in the USAF, one Air Force and one Navy. The first brother was instructed in hand-to-hand and KEBAR combat, but only in basic and as prerequisite training. The latter brother was a sonar tech and was thus on an actual ship. From what he describes and has demonstrated, they didn't just teach him hand-to-hand combat, they made sure he practiced it weekly.
The problem with the tight confines of hallways, whether it's in a hotel, missile cruiser, or a starship, is that the idea of being able to sit somewhere and trade fire is a luxury, not the norm. While your common Army grunt probably will never use their combat knife for actual combat, that doesn't hold true for other services, especially ones who will need to be handling that kind of pressure in two scenarios:
-CQB applications where there is a chance you will walk through a door and have a second or two to react to someone who might be quite close and that you might not be able to shoot at that moment...
-MPs and other "law-enforcement" whose job it is to disarm and disable, not shoot, their targets.
Given that both of those are very possible for both Naval personnel and law-enforcement, it stands to reason that not only is it still taught, but it's probably still checked for competency. If you duck under a duct and come face to face with your enemy, you're taught to attack instead of retreating to fire your weapon. Generally that means that modern military combat styles (Sambo, Krav Maga, etc.) tend to emphasize quick neutralization.
In essence, they're not kung-fu. They aren't meant to be flashy, acrobatic, or even meant for fitness. Most of those styles are practical hybrid styles that serve a series of functions that may never cease to be pertinent. It isn't as much butt-stroking someone in a pinch; as disarming and punching someone in the throat can be done almost instantaneously. More important is that you may not want to kill every single person you get into a fight with. It might never cease to be useful to be able to hammerlock and pin someone that you need to neutralize but not kill.
Of course, a lot of capsuleers who never leave the capsule might think it's all kind of visceral and personal, and that you've done something wrong if you're in a situation where you use it. But not every capsuleer is like that. While many capsuleers may have had the training and may keep up on it to some degree, you'll probably see more of it used practically by capsuleers who aren't afraid to mix it up outside of the capsule.