They do damage. Note that the card says 0*, not 0.
They're good scouts. No probe, but you can field enough of them to scout out a mapsheet fairly quickly the conventional way. (Also pretty good at ablative reconnaissance.)
Also, don't forget that despite their tiny size, they're not infantry units, they're full-sized vehicles in every sense. Including in terms of stacking, and blocking the movement of enemy units. Given how easy it is to bring large numbers of these things, you can easily generate the kind of traffic jam that can comment block the movement of important enemy units.
In-universe, cycles like these are a good way to add some fast units to very small or bottom-tier forces such as the garrison of a tiny new colony, a police unit, or the solahma-est of solahma. They're dirt cheap and easy to improvise from civilian construction, perfect for the kind of folks that the Clan normally wouldn't bother providing with significant resources.
A bit self-serving, but here's a good look at Minigun Cycles and other small support vehicles. :)