These come with a metal backplate and a magnetic strip. You can glue the magnetic strip to the back of the light and easily attach the metal plate, with the light on it, to wherever you want.
This way I get the advantage of a fixed light, which can sort of double as a torch.
Though they are not a proper substitute for permanent lighting, with convenient switches, they are really cheap and are handy to 'dot' around the boat wherever they are needed.
The one in the head, for example, has proved an enormous success.