Honestly, I was very surprised (read: disappointed) that this is not in the Apple Watch app. Complications are by far the most useful way to interact with Apple Watch apps (actually, I rarely download watch apps that don’t have complications because I find that 90% of a watch app’s usefulness comes from these complications). And it would just work really well for an app like bunq to see your account balance at a glance and launch the app directly from your watch face!
It’s probably something they are keeping for a future Update, but still, a shame that the watch app is launched in this state. Its very short announcement at Update 13 (compared to the time that is typically spent announcing less interesting features) indeed gave me the impression that the watch app is not all that exciting ... yet! 😉