I think that we should see the notifications on smartwatch, but keep the wallets of the smartphone for now.
The small display is a BIG issue for crypto transactions. It'll be quite difficult for people to be able to clearly read public keys or transaction hashes on the device. If the need arises for a Bitcoin-powered smartwatch, companies could simply create some sort of mechanism that would solve this issue (bigger fonts, scrolling text, etc.). But if people in the mainstream world continue to use smartphones more thoroughly, it would be rather unprofitable for mainstream companies to design a smartwatch that acts as a hardware wallet for crypto transactions.
Until now, a Bitcoin-powered smartwatch is more of an idea/dream than anything else. I've seen a new smartwatch company announced on BitcoinTalk a new smartwatch that acts as a hardware wallet for crypto. But I wouldn't trust it with my hard-earned funds as smartwatches are not proven to be safe unlike a computer or a smartphone. Besides, the company is relatively new to the crypto/Blockchain space. This makes people skeptical about using its products. But some serious companies like Samsung or Apple, could gain a lot of traction in the future if they ever decide to create a smartwatch that would serve as a hardware wallet for Bitcoin/crypto transactions. Just my thoughts