Rather than extra storage, how about just more room for a larger cooling solution, whether there's a fan or not. With Apple Silicon, it seems like performance is going to be dictated by the ability to dissipate heat, so I'd rather have a larger Mac mini that can dissipate more heat and boost for longer than a smaller one.
Nowadays most computer CPU performance is constrained by heat, but M1 on Mac mini is exceptionally constrained by its SoC design thanks to its efficiency.
