With a vertical dropout the wheel is fixed into one place and cannot move, so obviously you need a tensioner to keep the chain taught. The margins of removing links to getting the perfect chain tension are not fine enough and will not work and provide sufficient tension. However, it has been known to work on some frames with certain chainstay lengths and gear ratios. Example: With horizontal dropouts you can use snail cams or chain tugs which use such fine adjustment, so it is easy to get the perfect tension.