i'd say pinnies are short for pinafores, (i didn't check the link) and a pinafore is a type apron --one with a bib up to the chest, and the front bib was pinned on to your dress bodice or shirt (it was pinned on the fore (or front) of your clothing)

i don't call the kind of apron that is more like a dress coat (sleeveless or short sleeved, snap closure down the front a 'models coat' (models wear them between clothing changes) a short coat/jacket of the same style (especially if it had a shoulder yoke and gathers below) a smock, and most others things aprons.

pinafore's are to me, not an apron but an apron stlye of clothing, often worn by children! some have 'bibs', some have yokes and front's and backs (like the ones worn by the 'little house on the praire' kids) they can be worn with a simple blouse or over a dress.

and as for nostalgia, yes, even painful memories can invoke nostalgia.