Certain clients like the option of a peel off base coat. It doesn't suit all nail clients but it has it's uses.
I use Cuccio and some clients like it just on their toes. Also useful if they are going on a holiday and can't get to have them removed by me before returning to work.
It definitely isn't as hard wearing like traditional bases, but all clients are very different in how they abuse their nails or not.
Not recommended for those naughty pickers that Trinity mentions!