Can I setup up my phone as a camera and use the watch to take pictures?
Yep, there's a "Camera" app on the watch that does this. You can see what's in the phone's camera viewfinder on the Watch as well.
Can the watch work as a remote?
Yep, I do this all the time for my Apple TV's and it's very convenient. If Apple wanted to take it one step further they could determine which Apple TV you were closest to physically (via Bluetooth signal strength) and choose that automatically, rather than whichever one you last used.
There's also a third party app for Harmony remotes that didn't work too well when I tried it, but apparently has been improved since then. I think there are other apps for other remote systems as well, but I haven't tried them.
Yep, MacBook Pro late 2013 or later supports this (and this is the Mac I own, so I just barely made the cutoff). It's very convenient (but sometimes if my girlfriend "borrows" my laptop and is sitting within 5 feet of me it will log her in as me automatically, still worth it).
I originally owned a Series 0 but sold it a year or two ago because I never really wore it unless I was going out, and even then I really found I was just using to get notifications on my wrist. It's come a long way since then and I find myself putting the watch on every morning when I get up because it makes my life a bit easier in many different ways.
[doublepost=1511316227][/doublepost]The only third party apps I use are:
- AnyList so I can leave my phone at home when shopping for groceries.
- Tile so I can find my keys without needing my phone.
- Uber to call a ride.
- Chipotle and Dominos, but these only work if you always order the same thing as they are one button reorder apps.
- Slice for seeing when packages are coming.
- Carrot Weather because the native Weather app isn't informative enough for me.
- News Explorer but only rarely, if I get bored and want to read some news and don't have my phone.
And I'm not sure how long you ride but I'd think the Apple Watch could definitely replace an iPod Nano - my Series 3 lasts a long time playing music stored locally for me (10 hours according to Apple, though I have to recharge the AirPods more often than that).