If you want a properly seared steak, buy a cast iron griddle or skillet to use on your grill.
I agree.
Hot metal (i.e. induction) is the most efficient sear/Maillard process. Radiation (IR burner, direct charcoal, or a blowtorch) sears well too. Convection (regular gas grill; indirect zone on a charcoal grill) is the weakest method for sear/Maillard-ing.
A gas grill laid out with one side griddle and one-side grates is, imo, a most excellent set-up if your grill doesn't otherwise have an IR burner. Even better if you set up your griddle/sear zone on the side of your Weber grill that has the extra sear burner.
I prefer an edge-to-edge sear (personal preference) more than the stripes. The flat side of the GGs is an excellent tool for that sear/Maillarding job. My usual set up for steaks is one side GG flat side and one side grate (Weber grate or GGs right side up).
For my 2000 Silver B, the GGs gave me (i) some extra heat overall, (ii) better searing (when using the flat side), and (iii) WAY better flare-up suppression and more even heat distribution across the whole cooktop.
Think of (iii) as effectively the same thing as adding a second layer (like the older deep cookbox Webers had) of flav bars. Really comes in handy when cooking a big load of wings. No need to divide the cooktop into distinct direct/indirect zones. I can squeeze 14 pounds of wings into one big direct zone without any China Syndrome.
YMMV.