I don't program zig, so it's not clear to me if you can use zig's bitsets arithmetically.

Sometimes it's just more clear to work with integers than other representations. Most situations with a state space of N bits have meaningful integer representations, where arithmetic functions on those representations are also meaningful.

For example, CRCs can be written as the remainder from long division of the message by the polynomial. Defining nontrivial cyclic permutations is also much more straightforward as functions on integers than on bitsets.

For other situations like a CRC on an arbitrarily-sized message, a big int would be better, surely? You can do long division on those. https://ziglang.org/documentation/0.16.0/std/#std.math.big.i...

I was talking about GP's u729, which is 9*9*9, the state space of a sudoku board. Can you come up with a situation where dividing that number by anything is meaningful?