They may be small but they make a big difference when it comes to colour coordination. The silver pots on my magura mt5's really stood out but the little neon green accent rings give them a little more pop.
Getting them in was a tight fit but once they're seated, you won't ever have to worry about losing them.
The only real drawback is having to buy them in a set of three rather than being able to buy just the one colour but it's no big deal.