Easier for whom? Most programmers would not be able to follow that code. On the other hand, a really simple C or Python algorithm is more or less universally readable.
It's not so much about the algorithm, but the parsing itself.
Parser combinators give you one of the most straightforward ways to express parsers.
You are right, that the language you express your parser combinators in vs the language you express an alternative solution in also will have an impact.
You can in theory express parser combinators in Python. But it's gonna be a bit ugly, because Python has relatively clunky syntax for functions.
I just found a parser combinator library for Python https://pypi.org/project/parsita/ But it looks like they have to abuse some Python magic to make the code readable.
Alright, but jpeg decoding is nearly all algorithm, there's almost no parsing. Do you have a particular haskell jpeg decoder in mind that uses parser combinators?