I really like the idea of strapping a spare tube under the saddle. However I slink around on clinchers so no spare tubular. Years ago I made a canvas 'stuff sack' that holds my spare tube, tools, nitrile gloves and pump. As I have 10 (oops, 11 now with the Fuji) bicycles in rotation, I just use the same tool bag and toe strap on each. About a minute to lash it on and less to remove. Just part of my normal pre-flight.
Toe straps are fine for wrapping your right pant leg to keep it off the big ring.
Good for further securing your bike to a car rack, like lashing the wheels to keep them from pin wheeling in the wind and wearing off the paint on the bumper cover. Here though, I mostly use "Velcro" straps as I have dozens of those.