[jdranczewski]

I think in your first point the difference is between "calculation" and "conversion". For calculations, it's generally accepted that arbitrary numbers are possible and a calculator may have to come out. For conversions, it's nice to be able to say that 1250m is 1.250km - I bump into conversions much more commonly than having to do calculations, and it's nice to be able to do them in my head.

I don't think the second point is particularly valid. The SI unit is a kg - which is weird, but always consistent. All Physics units in metric involve kilograms. I will grant that it's unusual that it has a prefix, but still - if you know the 7 base SI units (including the kg), the rest follows reasonably, and conversions are trivial compared to Imperial (orders of magnitude vs arbitrary multipliers).

Fundamentally yeah, what one's familiar with is the system that feels most intuitive, but I don't think these specific arguments against metric work super well