It's the nexus of visual culture, history, politics, linguistics, technology, business... as a visual artist, type has a purity of form that has a Zen quality.
The ramp isn't meant to be different weights. The left is the original Material Design 1 ramp that uses tracking and static font weight tweaks to try to approximate an even color. The right is an actual even color.
In deep typography circles, 'parametric fonts' means typefaces where their attributes are isolated and can be controlled as parameters.
That can be done with OpenType Variable Fonts (eg Decovar and Amstelvar) but is not commonly done with them (eg OTvar fonts with just Weight and Width axes)
Its more common that parametric fonts are made with 'generative font' formats, like metafont and www.Prototypo.io, where there is a turing complete programming language that controls and generates the letter shapes.
Metafont has never found wide adoption, because to be a triple threat of typeface designer, mathematician, and software developer, you basically have to be a tenured stanford professor or their grad student to have enough time to learn everything well enough to make useful type.
And even then, the typefaces made with metafont are often very poor designs compared to those draw in a GUI in a 'dumbfont' format.
Adobe Multiple Master, then TrueType GX, and now OpenType Variations, are a 'best of both worlds' compromise; the drawing quality of visually crafted outlines, and the continuous-space-type-family-in-1-file typographic flexibility of metafont.
The www.glyphsapp.com and www.fontlab.com font editor apps have "smart components" which do this. Sadly the OpenType format is developed very conservatively by Microsoft so these aren't part of the only widely supported font format today, despite recent additions to the format of run time interpolation technology.