How do I connect a polyethylene water supply line to my refrigerator?
Watts claims their Ander-Lign fitting is universal and specifically says it can be used with plastic tubing carrying water.

The fact that they are using an insert makes the fitting stronger than the usual water filter/frig water supply fittings which are simple "push in" type fittings.

Here's an example of the other style:
http://www.freedrinkingwater.com/parts/fittings/jg-whitepoly-male-connector.htm

I think you should be fine.