The only and last time I used trackballs, were in trackball mice, that predated optical mice and laser mice. We were always having problems with them in school. The trackballs would always start messing up as the rollers got dust and hair in them. I honestly felt like we were cleaning them as much as we were using them!
When optical mice came out, what a game changer that was, and my first one that I owned was the famous Microsoft Intellimouse. That mouse remained king for many years until Logitech took gaming gear seriously. Logitech was like, oh yeah, hold my beer.
When the laser mice came out like the Logitech MX1000, I really thought they were going to dominate the market, especially with their ability to track on glass. But something happened in the peripheral industry, and laser has fallen out of favor.
When I was doing my research into a new wired mouse to buy, I discovered this, as laser is practically no longer an option now days. But with Logitech's new darkfield sensor, I don't think anyone is going to have much problems tracking on glass.
Cause I sware this Logitech G502 Hero mouse, man, it could track on everything including your ham sandwitch! But yeah, I was all too happy when the trackballs were no longer a thing.
Then like FrenchPress said, then all the sudden trackballs came back, this time to go on TOP of the mouse. Things just keep getting weirder and weirder lol.
speaks in, kawaii. So, thats probably why I appreciate all your kawaii things, including the heart shaped palm wrests hehe. 
