Gel Nail Question

For a change of pace I’m going to ask a question about gel nail polishes that has been bugging me for months.  If anybody can answer this, I’ll really appreciate it.
A few months ago I bought the stuff to do my own gel nails at home (IBD stuff).  One of the things I bought was "gel nail polish."  After reading the documentation and experimenting, I simply cannot understand what makes gel nail POLISH something a person would want to use.  It applies just like a gel, but it has color.  So, OK, you get color and strength.  But it doesn’t come off like nail polish; it’s not a soak-off gel product.  So I don’t understand what happens when your nails start growing out, or if you want to change color.  How do you remove it?  Or, do you have to file off the top of your nail to get rid of the color?  Or, do you have to keep backfilling with the same color?
Seriously, I would like to know the answer.  IBD won’t answer me because I’m not a nail tech.  They tell me that my nail tech will be able to recommend the right products.  I already get 2 weeks of wear from my OPI combo (OPI Nail Envy as a base coat, OPI or China Glaze color, OPI top coat, OPI Drip Dry).  And it’s easy to remove and change my mind about color.  The ebay seller that I bought most of this from says, "Sorry, I’m not a nail tech, I have no idea."