It isn't a bad idea at all, but i don't see the use for this, unless this was to be implemented to affect coins only... then i could see a use for it, as i have to get a calculator out to add up 11 stacks x5 and then 12 stacks x2... gets annoying. Would love this for coins, but not really for things like bread. Just isn't much point in it, and it would be confusing.
One Snappy Suggestion:
Would it be possible to have coins that value a higher priced coin turn into that coin, similar to terraria?
Example: When you get 5 coal (5 points), it turns into 1 nugget (also 5 points). This would save a lot of inventory space, and make calculating a lot easier :) It isn't really a problem, but i would love for this to be added if possible c:
Sorry i explained that so badly, never been good at explaining things... :p