I'm wondering if its a possibility to add this feature to the Instinct Solar. It would be a really nice feature to control my bike lights from my wrist so seamlessly.
It is about usability - information that you seen on your display and how you can easily control it. On watches with better displays it is not integrated, because it would be hard to control it especially on a bike (well, edge 130 has it hidden somewhere in its menu). On the other hand Edge computer with a touch screen gives you much more options how to do it - in Edge830/1030 case just just swipe down the top widget screen and you have all options that you can imagine. This is the reason why bike lights are supported only on bike computers.
What you're saying makes no sense. Bontrager and Garmin lights are controlled by Bluetooth which the watches support. I can broadcast my heart rate with this watch, view detailed information and browse through lengthy menus with different options for connectivity. The processor, screen, and connectivity are all more than capable of handling it if I can broadcast HR data as soon as I start a bike ride and get text messages.
It is using ANT+, but it is not important... Sure, it could support any piece of equipment, but this will not force you to buy a bit more expensive device (Instinct is a low cost) or to have a special device just for a bike (Edge). This is what it is, you have to deal with it.
For example - some "cheaper" devices (Venu, some "running" Forerunners 645, 245, 45, Edge Explored) doesn't support Power meters and why? It is still just a stupid broadcasting ANT+ device like a HRM or Speed/Cadence sensors...