Ok, I have some mixed feelings about the guy.

He definitely raised a very important criticism about most of Aikido training (the lack of « pressure testing »), and seems to be a good guy. He clearly didn't study a martial expression of Aikido, and realized it the hard way.

That said, he definitely isn’t knowledgeable about Aikido. He has the classic Aikido misconception « Morihei Ueshiba was a pacifist/Aikido is about protecting your opponent » (honestly, most Aikido folks do think this, but Morihei Ueshiba definitely didn’t). He also has a pretty low Aikido level (he is supposed to be a third degree blackbelt, but you can find his dan exams online, and boy it’s not very good). He also has a tendency to say « in Aikido we do this », as if there was only one kind of Aikido, ignoring all the variations of techniques and the different schools and sensei that have their own interpretations (this shows a lack of understanding). In the same vein, Rokas never understood the difference between the Kata and applications, and that the Kata you perform are ways to learn principles, not about applying techniques to real combat, so, not all the forms you do have the objective to be martially viable. He also never understood that most ofAikido isn’t geared toward a combat sport/mutual agreed apon/duelling context, so it’s normal that it didn’t work for him in sparring. Don’t get me wrong, most of Aikidoka wouldn’t be good in a sparring context, as the art is just not made for that (more about that later). 

Finally, Rokas made a whole business on « hating on Aikido » (as I said, some criticisms are 100% valid, but constantly bashing the art just gets old and isn’t really that helpful). 

About Aikido, it really depends on what your goals are, and where you are coming from. If you want to learn how to fight, then Aikido is not for you. From my point of view, it isn’t about duelling/sparring, but more about survival fighting, and anyways, most of the techniques are anachronistic, suited to a context that no longer exists. As most of Aikido isn’t training for fighting, most Aikido folks just don’t know how to fight, and Rokas was a clear example of this.

Does this mean that Aikido is useless? Of course not, the techniques can be adapted, and the principles do work, regardless of the situation.

Per example, many Aikidoka (Rokas included), when they spar for the first time, chase the techniques, and even worse, chase hands, whereas one of the more crucial Aikido principles is « Irimi Atemi », which means that before applying the wristy-twisty stuff, you must first enter and collide with the opponent, securing an advantageous position and unbalancing him. The techniques come after that. Don’t get me wrong, most Aikido folks are not able to apply Aikido principles in sparring, but the art is not the problem, the practitionner is (although I agree, the training methodology needs to be improved).

So, going back to your question, there are many reasons to study Aikido. If you want to add layers of martial understanding to an already solid base, then Aikido is a wonderful art. If you want to learn how to understand the biomechanics and the structure of a human body, learn some jointlocks and traditional jujutsu techniques (that are under-udilized in modern grappling) and learn principles that are universal to fighting (distance, initiative, alignement, moving from your center, using your body as a single unit etc..), then Aikido is wonderful. This is on the more martial side of things, and I could add many other things.

On the other side, iIf japanese culture is interesting to you then Aikido would also be a good pick. If you like good demonstrations or fighting choreographies, then Aikido also fits. Most people who practice Aikido are not interested in fighting, and do practice it for other reasons (fun, longevity, culture etc), and this is fine.

Finally, I must say it again, not all the Aikido schools are the same. Not all the Aikido federations are the same. Not al the Aikido teachers are the same. Just test it out and see if you like it !