Nylon hammer pros and cons? who has input

Who has input on the pros and cons with Nylon hammers?

I know you can get after market with some rifles. If they are better why don’t manufactures have them installed?

I don’t think any of my rifles have them “I think?” Edgun, cricket, p12, FX Impact and my Baluga, FLEX (WAR now has them for theirs rifles) etc…