Like with all
solar yard lights in general, the main purpose is to create a pleasant ambiance, making your summer evenings more agreeable.
Solar deck lights and
solar path lights can also be a nice addition to your swimming pool surroundings and landscape.
Solar pond lights will beautify your water features in no time.
No particular maintenance is required apart from cleaning the solar cells when dusty. The LEDs (Light Emitting Diodes) will work for several years and you will probably need to replace the solar floating lights batteries every 1 or 2 years.
More info on solar light batteries