I spent many years in Aikido and am also a well trained BJJ man. I know precisely the questioning and curiosity the videos trigger in you as an Aikidoka. I went through that same process.
But questioning wasn't enough for me, I needed experiential truth. And I got it. So know that my words come through experience, what I have found through many hours on the mat.
I can list reasons why this technique might work or that wouldn't work, and others may disagree. So the way to shortcut all of that is to try it out. Do it. Feel it. Have the experience, then compartmentalize it in your mind. It's easy to get side stepped from reality if you trust too much in mental reflections like words rather than what the martial experience ACTUALLY IS.
Aikido and Brazilian Jiu Jitsu share many of the same principles. Turn from resistance, don't oppose force on force, yield and redirect. The techniques are not identical, but achieve similar effects for the affected joints (ikkyo= armlock, kimura/omoplata= shihonage). The ukemi of Aikido and ground movements of Brazilian Jiu Jitsu are interlinked. Aikido really teaches you how to flow and be round when approaching movement on the ground. How to be a ball rather than a cube. The movement parallels are there, but then again, I think they're present in almost all jujutsu styles.
Questions such as yours motivated me to begin the E-Journal of Jujutsu (EJJ). In this first issue, Bruce Bookman, Aikido 6th dan and brown belt in Brazilian Jiu Jitsu discusses the connections and similarities between the two arts. I highly encourage you to read his article.
I also encourage you to experience Brazilian Jiu Jitsu for yourself. It is a modern budo, and would only enhance your Aikido skills.
But most importantly, it's incredibly fun!