the next Q is whether the GRX would be more resistant to knocks!
On the basis that I've written off two Shadow Shimano MTB RDs in crashes, I'd say any benefits will be marginal. If you crash, and lay down the bike on the ground on the drive side while still moving, I doubt any additional clearance will be much use. If you don't crash, your legs will take the impact first, and provide a useful crumple zone for the rear derailleur.
My advice - don't crash. As usual, I am very bad at taking my own advice...
On the basis that I've written off two Shadow Shimano MTB RDs in crashes, I'd say any benefits will be marginal. If you crash, and lay down the bike on the ground on the drive side while still moving, I doubt any additional clearance will be much use. If you don't crash, your legs will take the impact first, and provide a useful crumple zone for the rear derailleur.
My advice - don't crash. As usual, I am very bad at taking my own advice...