Yes, I do that, only I'm not putting tips on all toes, just big toe if necessary, and never with white tip, because IMHO this white tip made nailbeds look shorter and nails longer, and I personaly like to make thinner white line.
It all depends on your and your client's needs and preferences.
But extending toenails as a concept is fine, and I sometimes do it when natural nails are damaged or just too small. You can play with custom blend or masque powders or gel and get fab results.
There are lot's of threads about toes, both gel and LP, so you'll see what other people say or do.
hth