Many of us have had the distinct displeasure of ruining a canopy. I once dropped one on the floor and stepped on it. There is also the great possibility of getting CA fumes on the inside or some other adhesive which will either melt, craze or deform the canopy into uselessness. And then there’s the one where you open a kit you bought at a swap meet to find no clear parts inside.
You can find replacement canopies for “large scale” kits, including 1/32, 1/48 or 1/72, but there have been almost no canopies in 1/144. Brengun seems to be taking a position in this market.