It's mostly for novelty and fun given minecrafts many modes of quick transportatio especially in modded, but I think a tool to let you zipline across cables would be really neat; At first I thought it wouldn't work given that cables are just a visual effect with no collision or, I assume, data besides the type of cable which would be registered to the connector block itself. But I think if you used a raycasting method on the players camera to figure out the closest connected connector given an initial connector and then just mimicked the algorithm to render the cable with slack and whatnot, except to move the player along a line on the point where the tool would be rendered, it could potentially work really well!
I figure the item would be early/middle game create to be atleast a little useful against elytras and whatever
Thank you in advance for considering my suggestion :)

I do really like this idea, would be very difficult to get right though, I'll think about it.