There's nothing particularly special about the Richter scale in that respect. All logarithmic scales (eg dB) work that way. Both the Richter scale and decibels (and other logarithmic scales) are also famous like other nonlinear scales[1] for being widely misunderstood so I'm not sure a lot of people would think your way is clearer than the current usage, which is just to say "3.1m" if that's what you mean. That said, I like log scales and logarithms in general so if you want to campaign for this scale, knock yourself out. I don't like that you're calling it magnitude though, because magnitude means a specific thing (the first coordinate of a vector in polar or spherical form).

[1] eg the Beaufort scale for wind force