Good for swallowing up if something goes wrong (let's say, at a border crossing) or for places where the stuff hiding is a primary concern (let's say for those who are jailed).
Unless this hardware wallet ring becomes immediately conspicuous for anyone looking at it longer than a second, I wouldn't worry about it. People own various pieces of jewelry that they wear and cross international borders with all the time without any problems. If you get jailed, you'll have your valuables, such as jewelry taken from you by the officers, to be returned upon your release.
Actually, there is a worry - you could get robbed, or held at gunpoint and be forced to hand over your jewelry. Sure, the crooks will not the least suspect that your ring is actually a hardware wallet storing thousands of dollars worth of crypto (but then again, why are you carrying it
on your hand everywhere in the first place?), but it will be, at best, a hassle to recover your coins, and, at worst, a crypto theft.
Rob the old fashioned way and take away this wonderful ring. Or you'll just take it off somewhere and lose it. Like a banal ordinary ring. Carrying such a wallet with you is completely unreasonable, but only if the balance of this wallet contains only small change for pocket expenses, like buying coffee and a donut with chocolate glaze. Wouldn't it be a little expensive for such a wallet?
There is one more point: this device works through a smartphone application and an installed application and doesn't have physical buttons for confirming outgoing transactions as on traditional hardware wallets, which is protection against online theft. How will this ring be protected?