Why is mp recovery useless?

Well, I thought mp recovery was useless before until I saw that guy in the kmst video use it a few times. I maxed it thinking it would be a good skill, then took it off my keys after everyone convinced me it was useless compared to oak barrel. Also, we have 1 mp per meso pots which kind of nullifies any gain you might get.

After I watched the kmst video, I decided to try the skill out again. I didn't realize that you can use the skill without stopping to cast it. You can use it while walking (some of you probably already know this). I was thinking about how this skill could be useful when a lightbulb came on in my head . Completely forgot I had maxed energy drain lol. I lose almost 800 hp to gain 800 mp then use drain to gain my lost hp right back. With hb I get over 1.2k mp back. While training I've gone from using about 60-70 mp pots per hour to about 8.

I know some people are like "its not like mp pots are expensive". That's true. But the skill doesn't get in the way at all since you can use it while walking, so why not? Its free mp. A lot of free mp. Since I'm hp washing the skill will jus get better.

I just don't think this skill is as useless as people make it seem.