If you already have a foundation in similar principles, and have a good partner to work with, you can learn something through online material. It will never be as good as having a live instructor, but you can get something out of it if it's well-designed.
I'm in with that.
One of my guys, a 4th degree in the Tomiki-ryu and I were wanting to work on his promo-reqs one evening last month when we got lucky/unlucky and nobody else showed up but for he & I. He was wanting to "do something," and he'd been the training dummy for the 2nd degree guy whose working towards his next promo/belt, so I understood. So, onto the mat I went to pick up the old, familiar role as training dummy myself.
We decided to work on the latter "half" (it's not really half, it's 11 of 25 techniques) at the end of Koryu-dai Yon. This kata isn't about demonstrating "technique," it's about properly demonstrating principles, so it does NOT look "real," since it's not remotely designed to appear that way.
Anyway, it'd been literally about 7 years (since 2010) since I'd done that kata myself, as nobody in my school had that rank. Until this guy showed up from the old dojo where I started. He didn't know, and I couldn't remember, the order of the techniques... so there we were with his reference book and my pulling up the youtube videos showing the order, and so we could scroll forward/back and spot various core bits and bobs.
Below, if anyone is interested, are some old clips of my beer-buddy, Raja, & I, back in the day when we were both working on this same kata. These are... I think, 10 years old, maybe? I know the upload date is 10 years ago, but the video may actually be a bit older, not sure.
I'm uke in this one:
... and tori/nage in this one:
Stylized, and principles.... not kick-butt, but hey... it's an aikido kata. It is what it is.
My point being, we Did pick it up from the video/online resource. Granted, I had it internalized, but had not done it, so the rust was falling off in huge sharp flakes that were cutting my feet up.