Title is pretty self-explanatory. Think about it, Riot wants us to buy more skins, and the battlepass skins that come out are usually pretty decent. Why make us choose one skin to have equipped for an entire game and just never touch the other skins we earn/buy? It could encourage people to change up the skins they use, and encourage people to buy more skins over time. Just a simple button, or if you wanted to take it a step forward you could even let us favorite skins to add to a more concise pool for us to add to and use.