What are your thoughts? Is something like this practical/secure? Or is it better to continue using smartphones for Bitcoin transactions? 
I never met a person in my life that owns a smartwatch. The market share of smartwatches compared to smartphones and tablets must be minuscule. And people who own a smatwatch most likely own a smartphone too, so it shouldn't be a problem for them to have a Bitcoin wallet with them. I never used a smartwatch, but I'm pretty sure it's more convenient to do Bitcoin transactions from a bigger screen of a smartphone.
So, to answer your question, it doesn't seem to be very practical or relevant to the userbase, and as others pointed out, it's likely insecure.
What's the use of the smartphone if you will adapt it in a smartwatch? That's useless, although smartwatches are more handy. But if you have a smartphone, you don't really need to buy a gadget that also have features in a smartphone, because that's a waste of money. But if you don't want to be hassle when you go out with your friends, it is preferable to use smartwatch. But being practical bitcoin holder, smartphones are more secured and safe when having transactions in bitcoin. Also the screen of smartwatch are most likely small and it is hard to read, in transactions, to ensure things before sending it into a wallet address is very necessary, so it is risky to use smartwatches.