Why make the rune pages cost 6300 each?

It like making the old mastery pages cost 6300 each when they could be easily edited in champ. It feels like there is no good reason to want to spend 6300 BE on a page just to save yourself time from changing trees every game, on top of that you are more likely to change your runes based off of the champion you are playing anyway. Just make the rune pages work like the old ones, it's more of an inconvenience to have to redo runes over and over again because I only have 3 pages.

Basically, to get rid of a nuisance (which feels more like bad design) of redoing trees every time it costs you 6300 BE.