You're mixing up big-endian and little-endian. Big-endian is the notation used in English: twelve is 12 in big-endian and 21 in little-endian. But yes, 123.456 in big-endian would be 654.321 and with a decimal point, you couldn't parse little-endian numbers in the way described by lsusr.
Katapayadi does seem to be little endian, but the examples I found on Wikipedia of old Indian numerals and their predecessor, Brahmi numerals, seem to be big-endian.
I had the same confusion when I first heard those names. It's called little-endian because "you start with the little end", and the term comes from an analogy to Gulliver