Well, this is a problem for a currency if the system is inducing people to hoard instead of spend! In this case it is not a currency but a speculative asset.
It's inducing them to hoard instead of spending massive amounts. People will spend. It's what keeps the exchange rate semi-stable. People will spend their "profits" after staking. They will still continue to stake to keep a revenue stream. They will spend any extra that they can't stake.
Junk bonds are also speculative assets that earn a yield for holding them. But you can't also use a debit card to buy a danish with part of your bond.
The two mandates just don't jive: 1. it's a currency go out and transact with them and spend! 2. if you hoard them you'll get rewarded.
You can't spend your staked XPY. I think you are missing that point.
Keynes recognized the so-called purchasing power sink caused by hoarding money and how it can trigger financial crisis.
Ok... but there isn't a fiat controlling government here in XPY... despite what the nay-sayers and boo-birds say.