is Knot Sealer necessary ?

[nyckat]

http://www.hairdirect.com/store/tdi-...ealer-4oz.aspx

looks like this product is to seal knot and keep hair system from shedding, prolong the lifetime of hair system. is it necessary or worth to use on my lace system? does it work? looks like reviews are good but wanna make sure it's all good here.

thanks a lot