Haha! A serious question for a questionably unserious response.
The only time I don't have a spare is when I'm using it. I've never been without. Only racing do I see a reason for removing it.
I have it there. I've toasted a sidewall before (3 times), so having the spare was nice. I like to buy tires in sets of 5 if I can, and try to rotate all 5. Not always possible though. I do however have a spare in the trunk of the car, with a fullsize tire (no wheel) also for those distance trips. Should I lose a tire, I use the spare till I can get the rim/tire combo swapped to the fullsize. Continue trip. Doesn't leave me hanging or needing to buy a tire out of desperation. The truck just has 5 fullsizes, although I wish it wasn't a steelie. Looks ugly compared to the alloys.
Carrying a spare is the best option. You don't rely upon a 3rd member or a "miracle" fix tool. Popped beads are not fixed with fix-a-flat (but wd-40 works ). Plug kits can fail, although I'd trust them further than fix-a-flat. Air compressors do what? air it back up after it's plugged. You can't have plugs or a can without a compressor. Tires don't magically air up after the hole is plugged. Even then, I'd still feel like I'm on "borrowed" time till the temp fix fails. AAA costs money. Is the cost in gas savings or cost of a 5th fullsize tire less than AAA? Yes if you have a low flat rate (hah! That was funny). Friends and family aren't always available, leaving you waiting.
Anyways, I've given my piece as to why I feel only a real spare tire can save you. It's saved me at least 4 times I can think of, one was a sweet near wreck where the front end swung around and ripped the tire to shreds and pulled it off the rim. Was pretty gnarly. good thing I had a fullsize spare with me! I was 10 miles from town up a quiet mountain road with 4 passengers and no phone coverage. Not ideal.