It was originally added because of the problem of CaCO3 accreting on the electrolysis plates, and to preserve the ionizer's ability to give good pH and ORP.
But with the discovery of H2, the need for cleaning becomes far more important, because it has been found that ANY detritus on the plates may still give good pH and good H2, but no H2. The other difficulty of some large name brands is their fairly basic filtration. This is the reason detritus can get onto the plates in the first place.
Most MLM users are learn after they've bought their unit that it doesn't filter heavy metals, chloramines or fluoride, so they are up for another expenditure annually just to increase the filtration capability.
Add to this (just for good measure) that almost all of the time the user is only collecting alkaline water, and sometimes acid water.
Every time they use the unit this way, they waste up to 50% of the water they just spend hundreds of dollars a year to filter.
I think the current MLM units are a well built, well functioning device for what they were originally designed to do: create high pH water. But using them to create high H2 water is, in my opinion, not within their design brief: they are not the best way to get H2. Let's face it: they are a 30+ year old design!
And as I said in the video, H2 is what I drink the water for!