Sure. Here's a simple but obvious example. FYI, this video is of one of the acknowledged masters in our style, but he is not my master. I refer to him as "Master" here as a term of respect. His name is Master Euzu Angi. In the bo kata called 'Tokumine-No-Kun' (a common weapon kata in many styles), we have several moves in which we thrust with the bo:
At 32 seconds in, you see the first of several bo thrusts. As you do not practice our style, you may not be familiar with our stances, but for your information, the stances seen here are common to many of our empty-handed kata and exercises. When extending power with a bo or other thrusting weapon, it is important to keep your center of gravity (or one-point, or whatever each martial art style calls it) and be solid in your stance.
Notice that at one point, the Master seen in this video crosses one leg over another; this stance must be both rock-solid and well-balanced, lest someone grab the bo and pull. This stance is also a basic karate stance. Learning to do this well with a bo aids the karateka with settling into strong stances. It also teaches about extending power; if you can extend power with a bo, you can extend it with a punch. If you happen to be familiar with 'Naihanchi' kata, you would see a two-handed punch that very much resembles the bo strike seen early in the kata above; the difference is only that in one kata, the hands hold a bo, while in the other, the hands are formed into fists. The strike and the method of power generation are very similar.
In more advanced weapons katas, you may note that sword or knife or other cutting weapon strikes can also be knife-hand strikes or hammer fists; basically anything you can do with a solid weapon, you can do with your hands, to a somewhat more limited extent. The weapon just allows you to extend your power, but learning to apply power with a bo (for example) is applicable to power generation with empty hands. Solid stances, generating power from your core, keeping your center of gravity while extending power, these are all really important to empty-handed kata as well as weapons.
There are also some very subtle moves in some styles of kobudo that you generally would not notice in a video. For example, in the video above, at 29 seconds, you see the Master dropping the bo into a near-vertical position. Although you can't see it in this video, there is a 'snap' in the leading wrist when the bo makes (imaginary) contact with the hand holding the opponent's bo. This 'snap' is a backfist applied downwards, if that makes sense. It is used throughout the kata whenever the bo is dropped as if smacking the opponent's hand holding a similar weapon. If you can do that 'snap' with a bo, you can generate monster power doing the same move with your empty hand. A lot of people doing an open-handed block might not think about using a backfist in that manner, so it adds to your bag of tools in that way.
Really simple stuff applies also. Hold a bo and lock it in to your waist. Then have a partner grab the end and start trying to move you around by pulling, pushing, raising or lowering it while you resist. You will quickly find out how solid your stance is, how centered you are. If you can get to the point where your partner has to work pretty hard to move you around by the end of the bo, then your empty-handed stance is pretty good as well. Do the same with the bo locked up high under your armpit. See how your stance and center of gravity has to change to adapt to it.
I'm sure there are many more examples, but these are the ones I am just starting to notice as I get further into my weapons study.
Stances, center of gravity, power generation, and extending power without compromising any of those; those are the biggies that I'm seeing. It's really eye-opening to me.
