Two big problems with coated glass: 1) it's obviously glass, so prone to breakage with shipping, and tricky to handle in large sizes: 2) it is a poor thermal insulator, so condensation can occur behind the glass under certain common situations (strong diurnal temp or humidity swings
due to daytime only heating or AC, subtropical climates, or poorly insulated perimeter wall). For these reasons optically coated acrylic seems
preferable, but alas, is even more expensive.