It is archaic but not in all contexts. i.e. If you talk about 125 ccm motrbike, it is always "german" way. Also it is used for human age or dates.

Uh, it does not (unless you're 12 or so, I suppose).

Slightly older... older enough, that I remember Vlasta Burian's movies being aired in the tv, where it would fit.

I use it basically just for tram and bus numbers. It's more fun to say you're taking the dvaadvacitka instead of dvacetdvojka.