It's all in the name; a floor or wall anchor is permanently attached to the wall or floor at home or on location. In the absence of other - infrastructural - anchor points such as fences, concrete posts, benches, you now can have a permanent fixed point to which you can fasten your motorcycle with a sturdy chain lock.
Your own facade, garage wall or floor or a fixed location elsewhere are the most obvious places to install them. Contrary to the marine variation, these anchors stay behind when you 'sail away'. The idea is that they form a permanent safe haven to where you can return and 'moor' your bike without worrying it gets stolen.