The reason i fitted these is safety, and very real for me and my wife.
Back in 1992 when we lived in Sacramento,i was a member of the Buick Club of America
owned many classic Buicks ,one great car i owned a 1965 Riviera,only lap belts fitted from factory.
About 80 buicks left Sacramento for a trip to Bodego bay---yes from movie the birds , for
a weekend trip.
Only about 3 miles from the small costal town, one of my best Buick club friend and wife were hit from a side street
by a small eightys isuzu japanese pickup and were instantly both killed in there 1966 Buick Electra convertible,
yes only lapbelts, and you know how big a 66 Buick is.
Most reports from that awful accident and others realized that retractable belts may have saved them.
Soon as got back to Sacramento i changed out my 65 to retractable belts ,and we have never forgotten that day.