When you browse the current applications of solar technology, you will notice a trend. Some applications seem logical extensions of the capabilities of solar power meshed with the demands of a system. Others feel more like a forced pairing of power source A with power demand B. Solar outdoor lighting belongs in the former category.
It just makes sense to use solar outdoor lighting. During the day, when the sun is out, you have no need for path lighting, a door light, or security lights for your yard or garage door. By the same token, at night you will want these options available to you. Many yard lights were already built with light sensors to detect when they should start giving light, in an effort to save electricity.
Solar outdoor lighting takes that a step further, and incorporates lithium ion batteries and small solar panels into the lights themselves. The same light sensor can now switch a light between gathering mode and production mode. So during the day, the battery within the unit is charged by the light of the sun. When the light level becomes too low to gather any more electricity, the light switches on, and you have a seamless transition from dusk to a twilight yard with functional lighting.
This setup has more advantages than just an elegant blending of technology to meet a need. It also creates completely self contained lighting units. The first advantage of this is that you effectively have carbon neutral light once the manufacturing process is accounted for. This may seem incidental to you as a consumer, but to those who are trying to minimize their carbon footprint, this is a major concern. The US has the largest carbon consumption per capita of any nation on earth, and the countries in the European Union run a close second.
Another benefit of having self contained solar outdoor lighting is the ease of installation. In times gone by, you needed do dig an outdoor trench and bury electrical wiring in your yard. You had to properly insulate the wiring, so rain would not short out the system, you had to then splice in the lights individually for path lighting. Once that was done, you could begin back filling the trench, near the end of this process you could set the light units themselves.
there was the task of relaying sod over the trench or trying to coax grass from seed to cover the scar on your yard. With solar outdoor lighting, none of that is necessary. Each unit is small and lightweight and can be pushed into the ground by hand in most cases; the stake on each unit will work unless you have exceptionally dense or rocky soil. Even if that is the case for your yard you will simply need to dig holes for the units, rather than entire wiring trench. Also, since the units are self contained and meant for outdoor use, they are already weatherproofed, and no additional effort is required from you in that department.