One other dimension to infusing/drinking tea in a glass, mentioned by a Chinese colleague (who is a tea amateur - not all Chinese are although all seemingly will talk about tea) is simply the beauty of the leaves in the glass, which adds a potentially significant touch to the experience.
Granted, not all teas look superbly nice in a glass, and maybe not one single tea in reality can look as nice as:http://hojotea.com/item_e/g07e.htm
(could this be photoshopped - looks so bright)
But it is surely nice to momentarily gaze at the leaves from time to time. In that respect, long-leaved tea surely deserves to be served in a glass. Come to think of it, it could be some kind of a crime to put these long leaves in a teapot !!