Quite simple really, with a trackball the sensor only has one pattern it needs to be able to read, hence it can be optimised for that pattern and will NEVER find a bump or torn area of a mousepad or change in grain of wood.
a mouse needs to be able to track on EVERY surface and as such can't be made specicially for one.
and also the trackball is easier to move with less force meaning more control over fine movements allowing for super precise and super fast aiming whereas with a mouse you'd have to reseat the mouse all the time.
and finally the main advantafe for trackballs overall, more ergonomic, not wrecking your wrist means you can play for longer without fatigueing, not being faigued means your body is more accurate.
I disagree greatly. First of all nowdays mice have very advanced sensors that track on most surfaces and are not sensitive to colours or even texture changes, and, even if that's the case, most gamers, enthusiasts, programmers and geeks have a mousepad that practically eliminate this issue. Trackball sensors are generations behind an Avago ADNS-3090 (for example) which has higher max accel, higher max speed, higher dpi, etc.
Further, just look at the designs of Kensington or CST, totally not ergonomic since they don't fit a hand. There are plenty of mice that have been designed much more ergonomically like the CM Storm Spawn or the Logitech G9x. Now, ergonomic and comfortable are totally different attributes, most trackball tend to be much more comfortable even if they're not ergonomic at all.
As a peripheral enthusiast I got interested in trackballs after noticing some wrist ache after prolonged mouse use so I tried to reinstall an old A4tech WWT-13 trackball I found but it didn't work on newer windows versions so I bought a Logitech Trackman Marble after reading opinions and watching some videos.
After using my logitech trackman marble for a while I can say
Advantages:
- Uses little space
- Requires no surface
- Reduces hand/wrist/arm pain/tiredness after prolonged use when compared to mice
- Increased precision when using 2 fingers on the ball
- Easier to use in awkward positions or in reduced mobility situations
Disadvantages
- Poor software features compared to gaming products (no macros, no memory, no DPI switch)
- Low DPI sensor doesn't provide smooth tracking (problematic if you use more than 1:1 sensitivity)
- Low refresh rates (125Hz) are bad for smoothness
- Bad for long-distance movements if you don't use acceleration
- Low number of buttons (reduced productivity)
Conclusion:
Trackballs are inferior devices than mice for gaming.
Trackballs are superior in terms of comfortability and will help you if you suffer from fatigue due to prolonged computer use.
Trackballs can also be very useful for designers and professionals that require great precision.
Trackballs are better for reduced space environments and for people with impaired movement.