Honestly, I think spending this much money is a little strange. I have a $20 adjustable piano keyboard stand that does fine. It takes all of 30 seconds to adjust the height by loosening a knob and moving the leg props to a different notch.
Based on your description, it sounds like you probably live in your laptop. Other folks don't, and a hand-adjustable keyboard stand may not work very well for them. Imagine, for example, trying to raise something like that — even assuming it could take the weight — while using multiple monitors.
One would hope... 88-key keyboards are 45lbs (about twice a normal 27" monitor) and the older ones are significantly heavier... a non-POS stand should take >120lbs without a hitch.
That being said, there's certainly nothing wrong with a product better tailored for its purpose.
It's not just about how much weight the stand can hold. How well-balanced is it? How well-balanced is it while being raised or lowered by hand? Keyboards are typically fairly even in terms of weight distribution, and have a low center of gravity. Monitors, not so much.
Where the cost comes in is if you want to support multiple monitors (which, as someone who plays keyboard, I wouldn't trust to a cheap keyboard stand even if they could fit) and especially if you want to do it at a height that is comfortable for a tall person. At 6'3", most of the cheap options just don't go high enough for me.
Maybe that would work for many people, maybe it wouldn't—but it'd be nice if you included a link so that people could decide for themselves. It's an interesting idea but the first ones I found didn't seem to adjust to the height needed (obviously they exist, though).
