I see three key points against the idea.
1. Exterior walls of houses are generally not only load-bearing (Keeping the roof from falling down onto the ground), but also the primary shear strength of a structure. (Its ability to resist being blown/knocked over) Simply replacing bits with glass can quickly compromise the structure to the point of "rapid unplanned disassembly" of things. Walls tend to have a rather surprising amount of pull on the horizontal, and frequently rely on the material the frame is then skinned in to take that load.
2. The lay out and structure is usually not well suited to the task.
3. Ventilation and moisture handling of most houses weren't really planned around the levels you get in a green house. Even if your converted building doesn't get knocked down by a good stiff breeze after you have swapped out
enough siding with glass to get the needed light in, you may still find your building collapsing around you as it starts rotting out and deteriorating from the excessive moisture levels given off by the plants. And if not, then the toxic moulds might give you issues.
Personally I think you would be better off scavenging glass from old windows until you have enough to skin a building that was designed from the ground up to deal with the problems and needs seen in a
greenhouse. The amount of work you put into gutting things would probably exceed the amount of work needed to build new (Re-engineering a building generally costs far more than engineering a building of the same size from scratch when you are talking about this drastic of a change).
The closets to useful an existing structure would be in my mind is something like just the foundation from something already structurally compromised, but where the
concrete foundation is still good. (Rotten out building, extreme fire damaged roof, etc.)
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