The "$7 mouse from Walmart" will be absurdly light and toy-like.
“Will be” not “is” (in other words not a first-hand experience). Mass is a critical property of a mouse. Most critical is its inertia, because accelerating the mouse and quickly course-correcting is more responsive with a lower inertia. It’s also less fatiguing. A lower weight also reduces the normal force, which reduces the magnitude of static friction - this is related the effect where, where pushing something, it suddenly “gives way” and begins to move faster than expected. When using a mouse there is a feedback loop between the signals sent to the muscles in your arm and the position of the cursor as delivered by the optic nerve. The greater the lag between the signals, the greater number of adjustments that need to be made to reach equilibrium (i.e. the cursor is where you want it).
All of this boils down it being more taxing mentally and physically to acquire your intended targets with the cursor with the brick that is the Magic Mouse.
If you set the mouse pointer and tracking options correctly, the cursor moves in perfect sync with the movement of the Magic Mouse.
So, what, you are moving the mouse 24” across the desk? I don’t know if it’s the drivers they designed for the mouse or what, but the control system for the cursor is poor. It doesn’t scale appropriately to the velocity of the mouse. If you increase the speed of the cursor in settings to a high enough value where it covers a reasonable amount of screen real estate without having to move the mouse so far, then it moves much too fast when trying to use fine motor skills for precise control.
Imagine it like a plunger stuck to a wall, and you’re trying to point the handle at a specific spot on the opposing wall. Grip the handle near the base and it moves quickly and easily, but it’s hard be precise with it. Grip it at the end and it’s easy to point, but you’ll be cranking your arm all over the place. You need a fluid mechanism that can tune the control from fast to slow as you zero in on your target. The Magic Mouse’s control mechanism does not do that well at all.
I've been using the Magic Mouse (v1 and now v2) for over 10 years and have always found them to be quite usable.
I mean sure, that is technically true - moving the mouse does in fact move the cursor. That’s about the best you can say for it.
Ergonomically, it’s terrible. It’s too flat, providing no contact from or support to the palm. This also makes the sides very narrow, sloping inward with seemingly no regard for providing a surface for the pads of your fingers to rest upon. It‘s like holding a worn down bar of soap. The lack of distinct left and right clicking mechanisms means that there is less tactile feedback between the the two functions, whereas there is greater surety with a mouse with two buttons. Since there’s also no tactile indication of where the right-click functionality “begins”, you get occasional mis-clicks where you activate the wrong function. Furthermore, since the touch surface extends all the way to the front lip, you’ll sometimes get unintended micro-scrolling when clicking the button and adjusting your grip.
There was no apparent design regarding holding the mouse, pushing the mouse, and clicking the mouse, beyond the fact the fact that they can be done. It’s quite a disaster of a product, to be honest.
You don’t even have to read any of the above, though. Just connect any other mouse you can find and you’ll see how bad it has really been. Takes around 15 minutes to acclimate to the motion of the cursor of a different mouse, then a couple days to really develop a proficiency where your brain has integrated the characteristic of the new mouse into that feedback loop (as your brain fine tunes the signals sent to the muscles that it takes to produce the desired output of the cursor).
