well I never like to speak to value. cost is relative to each individual. what's worth it is up to you. I did pick up a set big enough to cover a 22 kettle for $50 (spatula included) on sale so in my case it was a value. I've always wanted to try them but not at over $100. I've had them in my cart several times and could never pull the trigger.
as to why there are a few potential benefits. the first thing I noticed was how even the IR thermometer showed temps. the entire surface of the grill grates was within 50° despite only being heated by the small firepot on the pit boss. this increased my usable sear space considerably. another benefit is reduced flare ups. I am not a fan of grill lines myself. they can be flipped upside down and used on the flat side if desired. this creates a kind of griddle surface for cooking. I dont know about cleaning but I assume it's just a matter of building a proper season and your good.
I've cooked hundreds, if not thousands of steaks on traditional grates. do I need grill grates to cook a steak? of course not. can they improve grill performance? of course
at the end of the day this is also my hobby. buying various gadgets is fun and keeps things fresh. I would definitely recommend them to anyone with a pellet cooker or gasser that needs more umph.
