Repeatable mounts take all advantages of detachable mounts to a new level. All the advantages of detachable mounts, which are:
Detachable mounts offer possibility to use multiple scopes on one rifle,
enable easy transportation of the scope and the rifle separately,
in an emergency if the scope fails you can immediately detach it and use iron sights are upgraded with,
100% repeatability, which means that you zero all your scopes only once and then you can use them on one rifle in any combination you prefer and as many times as you wish.
Such mounts are ideal for hunting rifles, where you can use the same rifles with different optics on many different types of hunts. The perfect combination of different optics on one rifle can be described in this fashion:
Red dot sight or wide angle riflescope for driven hunts,
1.5-6x42 or similar for stalking,
3-12x56 for low light hunting.
You can add as many different optics to this setup as you wish, since this is the main concept of repeatable mounts. Easy transportation of optics and rifle separately is only an additional bonus.
There are however many different types of repeatable mounts, of which the most common are: