Just my two cents...
I have used stem adapters, threadless stems and then bars on threaded forks with no problem.
In fact, it allows a bit of height adjustment based on the stem you use. Add some spacers below the stem and it looks fine. Other than Technomic types, quills limit the height of the bars.
Advantages
1. you don’t have to worry about stem quill height to make it comfortable, nor is it a problem to change it up.
2. Being able to remove just the bars is an advantage if you like to tinker.
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1987 Crest C'dale, 1987 Basso Gap, 1992 Rossin EL, 1990 Van Tuyl, 1985 Trek 670, 2003 Pinarello Surprise, 1990ish MBK Atlantique, 1987 Peugeot Isoard, 1987 Nishiki Tri-A, 1981 Faggin, 1996 C'dale M500, 1984 Mercian Pro, 1982 AD SuperLeicht, 1985 Massi ?, 1988 Daccordi Griffe , 1989 Fauxsin MTB, 1981 Ciocc Mockba, 1992 Bianchi Giro, 1977 Colnago Super, 1971 Raleigh Internat'l, 1998 Corratec U+D, 1991 Peugeot Slimestone, 1987 Bianchi Volpe, 1995 Trek 750