Its shaving a lot of time off of my runs, and it is considered legit. The new 4 robot run uses it. It is especially useful when you have a NPC with you like Ki, and your chance to run goes way down.
On the older consoles, you start and get an encounter, then 3 steps, another, then another with 1 step or a reset. The 4th encounter comes 36 steps later. This is how most people get the Seven Sword to drop as the Haniwa is the 4th encounter on the last floor of central shrine.
After the 4th encounter, you get the longest series of steps in the entire table at 65 steps. In testing, this can be exploited to ensure you will not lose time on cant runs, or surprise attacks. It can also be used when you know you are close to getting out of a dangerous area, to ensure you get out quickly with no unexpected attack.
After the 3rd encounter, I simply start counting up in my head, I dont count every step, I just estimate. Then I will save, 3-4 steps before I know the encounter is coming. Again this is situational and works best when you have the NPC with you, but it saves a lot of time, especially early between Mr.S and Ki.
In testing, this also revealed it may be possible to manip a Karate, Jyudo, or Sun Sword drop on the first or second encounter. Depending on your equipment and manner of attacks, any physical item between punch and karate could drop, or any of the Paladin drops, like Defend, Samurai shield, or Sun sword. Obviously the only practical use of this in speedrunning woud be for a specialty party like 4 robots, and the only truly useful item drops would be Sun, Jyudo, Karate, maybe X-Kick.
More testing to come.