This thread may be of interest if you have T5s and want more light out of them. It is off a marine fish keeping website, bit the principle of over-driving T5s is there. This is something I am thinking about doing.
I don't do most Dendros or large, "floofy orchids". For me it's minis (like Angraecoides), Masdies, Paphs, and others that crept in somewhere along the line. See my orchid list for complete collection (usually not current.)
I was thinking it may be useful for people who have taller cases, that it may get stronger light further. Say for higher light needs plants like vandas.
I agree, normal T5 would be fine for most growing cases though.