Last time I used Huffman codes, it was to run a MICMAC processor macroprogram (assembly text) in the fewest number of microcycles and to use the fewest microinstructions in the microprogram (microcode). So starting with a histogram of the macroinstructions executed (IIRC, I first wrote an interpreter in C to count how many of each were executed), I crafted a progressive decoding microcode program to implement all of the required ISA macro-operations. IIRC, the macro instruction ISA I created was bit-granular instead of byte-oriented. In the real world, it would've been slow and inconvenient. What's nice about Huffman codes is that you can vary the prefix depth based on the distribution of values, so you don't have to have lopsided codes based on 1 bit prefixes.

Also, the microprogram had to deal with branch prediction because it was a non-superscalar pipelined processor model. Guess the wrong branch, and enjoy wasting cycles on a pipeline stall while the correct branch filters forward.