One positive and unplanned side effect is code density. Besides taking less memory, if you can “decompress” the ISA faster than memory bandwidth would otherwis

One positive and unplanned side effect is code density. Besides taking less memory, if you can “decompress” the ISA faster than memory bandwidth would otherwise allow, it’s a net win. There are many other downsides to x86, like variable length instructions, of course, but it’s something to consider.