For me, it very much depends on the game:
- Masocore game like Only Up? I love watching other people struggle with it and have zero desire to play it myself
- Factorio or Dyson Sphere Program or similar games where the fun (for me) comes in coming up with my own creations? 99% of the time I want to play, not watch. Some exceptions: if someone is attempting a ludicrous challenge, or the occasional tips video
On a related note, have you heard of the Three Moves Ahead podcast? It seems like it'd be right up your alley: it's entirely focused on strategy games