1. Savings are deferred consumption/investment, which can be used for consumption/investment later.
2. Previously, savings without knowledge were able to provide a positive return on capital, in the 1700s this was about 5% but has steadily declined. Now it is hardly possible to get more than 2%. Taxation by inflation (capital "gains") is the main way how this is accomplished lately.
I posit savings had long-ago moved to NIRP in the form of inflation and now with deflation taking over, the NIRP has moved to interest rates.
In short, savings (idle monetary capital) will never again generate positive ROI. You must actively invest now to get positive ROI.
This is why I said say 5% debasement for altcoin (as an alternative to tx fees if the holistic design is viable) was not anything inconsistent with reality. Your appreciation gains far outstrip the debasement (and make the level of debasement basically irrelevant), otherwise you shouldn't be holding it as investment any more (use it as a checking/savings account) in which case 5% is roughly about what banks charge in fees on a small checking account balance.