If you choose to store your wealth in XMR, you are losing value to Bitcoin over time, simple as that.

The longer the tail emission goes, the less the inflation is. The benefit is security of the network.

Arguably Bitcoin will be much more prone to volatility because the hard cap is unprecedented in the history of money (remember that nobody knows how much gold exists, but we can predict some rate at which it is unearthed).

Manipulation, panic, hoarding is much easier with a hard cap, just from a human psychology perspective. Constant emission is predictable and cozy in comparison.

The benefit is security of the network.

No one can say this with certainty for another decade or so, when we'll start to really find out if the fee market on Bitcoin is enough to make up for a significantly smaller block subsidy.