When I got back into cycling in '82, bought one and used it regularly (along with a sou-wester). Even wore the sou-wester in my first ever TT (25m) - I wear glasses. When considerable amount of mickey was taken, I loftily informed them that is was "an auto-airstream conformable helmet".
I tended to hook the thumb loops over the brake hoods. This enabled me to signal fairly clearly.
Haven't worn it for some years tho', largely because it rarely rained while I was commuting and it was quicker to shrug on a racing cape, aka jacket