We haven't altogether decoded them, so the answer to that is up in the air. However it does appear to use something akin to decimal for numbers, but the encodings use numbered knots, colours, and positioning within a larger weave. Around 60k variations have been found. However, there can also be some thousands of braids within larger weaves.
The depth of the information contained can be debated, but as the Spanish utilised the related quipu following their invasion, for their own record keeping needs, it is "of use". (The Spanish used those for tracking crop growth, timelines, deliveries, royal decrees, family trees, and spread of illnesses in remote areas. They're also still used in some religious sects today.)
