My parents got me into karate when I was about 6 or so. I got to Nikyu rank or brown belt by 14. As a teen I wanted to try aikido. From what I know, there are two distinct styles where I trained, Ki Society and Aikikai. Ki Society is very spiritually focused and the techniques are usually done cooperatively where you blend with your partner. I just happened to sign up with Aikikai, which was a "hard form." After a certain rank, your partner is non cooperative and you must do the technique correctly to succeed. I was a teenage girl practicing with grown men so I had to do it perfectly. Still, it was much about mental focus and ki energy that made your technique work. When I got to Yonkyu or blue belt for us, I was uke or the throwee for my sensei. I was expecting a nice gentle throw when he did kotegaeshi or a wrist throw. Next thing I knew I was flat on my face seeing stars. Sensei said, you're Yonkyu now, you can take the fall. I eventually got to Nikyu as well.
I've used aikido in real life a handful of times. I was groped a couple of times and once in a "bar fight". Haha, actually, a former female friend was about to hit another friend and I intervened and she grabbed my hair and ended up in a Nikkyo wrist lock.
I've been taking kendo now for about a decade. I'm on the verge of Godan or 5th degree black belt equivalent. We don't wear color belts and there is no rank distinction on the gear. I also have been taking iaido for the same time. Kendo is the competitive sport with the armor and iaido is the art of drawing the sword and cutting. With previous martial arts experience I found reaching a state of focus came quicker, maybe around two to three years in. It is like "the force" in that, it's easier to apply with one less skilled, but very difficult with one of greater skill. With some opponents, I just know what they're going to do before they do it. With Rokudan or Nanadan high level sensei they know what you will do first. It's a sense where their energy shifts and you notice a twitch or change in the breathing or pressure between the swords.
I find the ability to laser focus very useful in so many things. From just the personal benefits of stress and anxiety reduction to practical use. I've also been fencing for more than 20 years since I was very young and the crossover of skill and mental focus is great. I've been very good at finding weak spots in an opponent and luring them into traps. I also fly for a living and focus is critical when things go wrong or on landing. With mu shin, where you're zoned in, you observe so much more, both in fine detail and big picture. During many of my bouts, after the sword exchanges occur, I don't recall thinking anything, but I do recall every detail of the exchange from attacks, parries, dodges, etc. In iaido, we sometimes do tameshigiri or mat cutting. This requires a lot of focus to make a successful cut through a thick tatami mat.
This is the gentle version of kotegaeshi.
Here's the harder version.
I hope that answers your questions. I could talk all day about stuff like this. :P