The pitch of the screw isn't all about speed, you also need to consider the resolution you might need.? However, for a wood router, a 10mm pitch still gives far more resolution than your likely to need and a 10mm pitch is the correct choice for a router that is mostly cutting wood.

The feed rates or speed you cut at are under your control so you can speed up or slow down to suit the job, however, if you choose too low pitch then this can limit the feeds and you can't reach the correct feeds for cutting some materials/tools.