The stuff that they make residential lawns out of is a bit different than the stuff they use on sports fields. Athletics fields are "infilled" for grip and cushioning--lawns are not. But basically the same idea.

The benefits are obvious--you basically listed them already. Little maintenance and they are always green.

There are only a few downsides:
Cost. Much higher than a regular lawn. Sure you save on maintenance, but it will not be enough to "break even" over the life of the lawn.
Limited life. The UV and wear will eventually cause it to fade and deteriorate--and the plastic grass will then have ripped up and disposed of. They last a while, though.
Appearance. This one is subjective, but no one will mistake a fake lawn for a real one. They have come a long way from the Astroturf days, but they still don't look real.
Heat. On hot sunny days, they soak up lots of heat and then radiate it back up at you. More like concrete than grass in that regard. They get HOT!