Question

why has the use of teflon coating is more common

Answer 1

the uses that make it more common to use are
1) Turn it into a Non-Stick Surface
2)The surface is very easy to clean and water does not cause the industrial coating to become saturated. 
3) The right coating can help your product exceed customer expectations, whether you sell directly to consumers or create parts and equipment for businesses and organizations.
4) For the most part, Teflon coating is not affected by chemicals found in its environment. 
I HOPE IT HELPS
WITH REGARDS
ANKITA