On 8x8 a Nightrider is about a quarter Pawn stronger than a Rook. Mating potential only contributes very little to the value of a piece, because most chess games end with enough pawns on the board to force checkmate after promotion.
Is a knightrider better than a rook?
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Knightrider is roughly the strength of a rook on 8x8 depending on how cluttered the board is.
However, on very very large cluttered boards, a Knightrider is both faster than a rook and can move in more directions, so it should have twice the one move mobility without getting blocked, and substantially better second move mobility as well. Arguably making it comparable to a queen in that situation.
One weakness is it cannot concentrate force all that much in one area so it needs to rely heavily on forking or pinning separated pieces.
Obviously the reverse goes for smaller, emptier boards. A knightrider on a small board like 6x6 will rarely be leaping anywhere.
I know a knightrider can't mate, but a rook can, but an N rider can jump over pieces tho