I don't like stuff on my wrist anymore. Gave up wearing a wristwatch back when cell phones started displaying the time constantly. I only really want the recorded data from my rides and could do that with a wrist device, a bar mounted device such as edge or wahoo, or a smartphone in my bag or pocket.

However it's nice to occassionally glance down and see if I'm as good as I think I am. With a bar mount I can glance down and see my edge500 easily while 30mph plus on a downhill twisting route (slowly twisting, I'm not that good..or crazy). I don't think I could see a device on my wrist while doing that and I certainly wouldn't pull my phone out to look at it.

You can mount your wrist device on the bar and get HR strap and other sensors too, However just like all devices whether bar mount edges or wrist worn, they don't all have capability of using any and all sensors. Many don't have provisions for power sensors. Basic models many times can't use cadence and/or speed.

Phones? You didn't ask, but my 2¢ Phone belongs in my bag when cycling. I'm riding by myself frequently in places where there is sometimes not much traffic of any sort for awhile. I don't want my phone to be mounted to my bike and I wreck and it fly off somewhere not to be found when I need to call myself an ambulance. Yeah, you think of stuff like that when you get older. When young and invincible you take the risk and laugh at those that take precautions... I did, now I don't....at least not as much as I did............need I go on?

I use my edge 500 as I've done since they came out at about the same time I started back cycling for fitness. My son got a VivoactiveHR a couple years ago and used it for cycling as well as other stuff. Soon after mounted it to his bars and got an HR strap. Then recently got an Edge 820.

Consider too that the wrist devices are multi sport ....somewhat. To me any device with Multi in front of it's name is a compromise of performance and features. BUT, that does allow you to easily use if for other things like a simple walk down the trails. The Edge is a Cycling device and that is what every thing in it's programming and user interface is geared toward. though I've used it for walking trails, It's not as friendly setting up for walks.