A person who might find this useful would be a modder/enthusiast who would like to change the spring weight of their switch. (ie ergo clears).
According to the website:
My 50g is a little bit lighter than MX Red
My 55g is slightly softer and lighter than MX Brown, MX Blue
My 60g is similar to MX Blue, but has some more tightness, hopely
My 62g is a little bit heavier than MX Blue
My 65g is soft but quite heavier than MX Blue
My 68g-70g is similar to some Vintage MX Blacks
My 75g is similar to most current MX Blacks
My 78g is Soft MX Clear Edition, Slightly softer & lighter than MX Clear
My 85g is similar to MX Clear. v1.0 has a little bit tough start, v1.1 will be very similar to Vintage Clear.
My 100g is similar to MX Grey Nonclick in MX Clear Keyboards
My 120g~ Super-heavy!