Looking around at the tripod heads in the shop it occurred to me that only two of the manufacturers really get it - they are aiming themselves at the big end of the market - by the smallest means.
Consider - when we put an image up on the computer screen in, say, Photoshop, we get the option to select something and move it in infinitesimal increments by using up down and sideways keys. We can't achieve the same degree of precision with trackpads, tablets, or mice and the computer people know it - so we get the electronic equivalent of a fine-tune control.
We also can't achieve the fine control of cameras that we need on conventonal tripod heads - if we are working with a ball head it falls all over the place as soon as we loosen it - even the three-way heads are crude pivots when we need fine movement.
Arca-Swiss and Manfrotto addressed this in their separate ways by putting mechanical creepers on their cube head and the 405 three-way head. In each case there is a crude se-up adjustment comparable to mousing over something and then you can use geared knobs to fine tune the position.
They are intended for use with big studio cameras but wise small-camera users will also see the usefulness. Big fingers need help with small controls.