If the Variable Font shows up in the CAS application's font list (SignLab in this case) only the basic weight of the typeface will show up. I don't think any CAS applications on the market fully support Variable Fonts at this point; they don't even support all the standard features of OpenType, much less new type standards like Variable Fonts or OpenType-SVG. Adobe Illustrator is the only drawing application that fully supports all of those new type technologies. The latest versions of CorelDRAW and Inkscape support Variable Fonts.
FYI, Windows 10 includes the Bahnscrift typeface; it's an OTF Variable font with three variable axis sliders (width, weight and slant). Last time I checked all of the Variable fonts hosted at the Google Fonts page have only a weight axis. No width slider unfortunately.
I'd really like it if Microsoft re-worked Arial in OTF Variable format. If that happened (and CAS software companies improved their badly outdated type engines) we might see a good bit less of default Arial artificially squeezed and stretched on signs. A Variable font with a width axis will allow someone to set condensed or extended type that looks far more natural. Bahnscrift looks like a German DIN style typeface, so its use is a bit limited. Illustrator includes the Acumin Pro Variable Concept typeface, which looks more neutral.