There's also the thing where the 1 in 0.0491 has the exact same significance as the 2 in 0.0982.
IOW, the final significant figure has continuously variable significance (but discretely intervalled numerically) depending on the absolute value of what is it supposed to be significant to.
This is a feature of granularity.
And rounding error has a variable influence on the intervals and how "discreet" or blatant any error may appear.
Then you've got error propagation and pretty soon you're going to need something like Gustafson's UNUM's:
IOW, the final significant figure has continuously variable significance (but discretely intervalled numerically) depending on the absolute value of what is it supposed to be significant to.
This is a feature of granularity.
And rounding error has a variable influence on the intervals and how "discreet" or blatant any error may appear.
Then you've got error propagation and pretty soon you're going to need something like Gustafson's UNUM's:
https://en.wikipedia.org/wiki/Unum_(number_format)