To use a Halo you have to replace the softer and more flexible detente with a stiffer detente to keep balls from double feeding. The stiffer detentes seem to be a little less durable in the long run, the softer stock ones last a longer time (maybe because they are softer and more flexible).
Although Timmies aren't my very favorite, this is such a small thing, so simple to do, that calling this a weakness is sort of blowing things out of proportion. It is slightly more hassle than attaching air and hopper.
And anyway, have you ever seen how much a midget will eat?