First I would like to propose that the tools offered in the store of gems were global to your characters, well the change to a single tool can be used by all your characters, but if you play with several characters does not make much sense to be changing the tool by the bank every time you want to play and collect materials while playing normally.
One idea would be to improve the collection that had a sort of global level in the account which will allow certain advantages of your choice, such as the character that you leave invisible to collect, or collection by a beam of light can be distance …
You might set up 3 upgrades depending on your level of collection, which would make it more personalized, more enjoyable and more fun.