Hi,
Here is the short version: Why don't you just tape it?
And now the german version (slightly longer
):
First of all: What is the exact size of that "tiny" hole and where is it situated exactly?
Well, the diameter of a cigarrete is appox. 7 mm (Auntie Google tells me) but how big is a burn, 10 mm?
The result of "friction from the wheel"?
((which you didn't notice while riding the bike
))
So I reckon it'll be somewhere on the inside of one of the paired rear triangles, probably on a chain stay, not far from the bottom bracket shell, right?
Well, if that's more or less what it looks like on your frame, your conclusion "not a stress point" might turn out as a far too optimistic guess (depending on your weight and the kind of use (esp. speed) the bike will have to stand.
This being said ...
a filler or putty like the one you have found won't work on a bike in that place and for that kind and size of hole. (If you still dare to try, make sure you'll at least get one that'll work on alu - and not just on steel.
Which bring's us back to square one:
What you could do is tape it with a really strong duct tape that is suitable for aluminium - or whatever is the surface of the frame (is it lacquered?).
You could try one from sticky products for example (stickyproducts.co.uk), they have a phone no. for expert advice (+44 1724 749020) that might be helpful.
Good luck!