What does the French word Bijou have to do with movie houses in the United States?

Sorry had to Google since in French it means jewel or gem. But here it is straight from some horse’s mouth:

“You say it BEE-zhoo, although depending on the neighborhood you can also get away with everything from BUY-joo to BEE-joe–when you start trying to dress up your establishment with a little dimestore French, you take your chances on pronunciation. “Bijou,” originally a French word meaning “jewel” or “trinket,” was probably one of the five or six most common theater names in the country at one time (the others that occur to me offhand are Rialto, Tivoli, Adelphi, and Odeon). The word entered the English language in the 1600s and has since resisted the most determined efforts to throw it out again. Eventually it picked up an adjectival use as a rough synonym for “charming” or “of intricate design” with reference to architecture–e.g., a bijou cottage. Since theater owners have always like to advertise the attractiveness of their establishments, and since bijou has the added advantage of sounding exotic, Bijou Theater was a natural.

The first such joint that I know of was Hartz’s Bijou Theatre, which opened (and closed) in New York in 1870. But the name was probably common before then. It later became quite popular during the vaudeville era. The entrepreneurial team of Albee and Keith, said to have done for vaudeville what Rockefeller did for oil, opened Bijous in Boston and Philadephia in the 1880s, and thereafter Bijou theaters multiplied like rabbits. Most vaudeville houses, of course, were eventually converted to movie theaters, and many of the latter were eventually torn down, so that today we have precious few Bijou theaters indeed, which doubtless accounts for the present sorry state of the Republic. I could be wrong about this, but somehow I doubt coming generations are going to get nostalgic about the great video rental stores of their youth.”

Cecil Adams