You're still dodging the question of why it's necessary to save in-currency! Answer it, please.
I anticipate keeping the bulk of my savings in a private form, immune to theft, which protects me and my family from extortion, kidnapping, &c, by its privacy.
Productive assets need not be in-currency, in fact cannot be in-currency, because currency is not productive. Savings and transactions in XMR are compelling exactly when privacy is most important -- i.e. when you have the most to lose.
Currency cannot behave like currency if the value constantly trends upward. An asset's value appreciation tends to be the inverse of its liquidity.
Infinite divisibility means that the floating portion is always capable of providing a transmission mechanism. Increasing value means less of the float is required to perform the transmission function. It is a self-adjusting mechanism.
How much are you willing to pay to keep the greedy fatcats out of the cookie jar?
In the long run, demurrage games have vanishingly small impact compared to the forces they would mitigate. Any distribution improvements would be a tiny marginal one. The cost of those improvements would be destabilization and shrinkage of the in-currency economy, as capital fled to other media. Separating transmission and storage creates a friction, an inefficiency and ill-liquidity in conversion, which I expect does more damage in aggregate than any improvements in distribution would be able to offset. Most of the social value created by a currency is created by liquidity. Any impairment of liquidity is catastrophic, if only because competing media will not suffer the same impairments, and hence will dominate.