Is it possible to get a decent fixing on the posts so it stays still, can you just lay the lumber in joist hangers without fastening them, can move a little, the joist hanger in the wall has several cm to lie on, a deck doesn't move that much.
Primary load-bearing (carrier beams) should not be attached with joist hangers to the facade (even if they are loose in the joist hangers) unless the facade contains more than just the panel that can withstand fastening. The loads become too large. Secondary load-bearing (top layer of joists) is OK.
It will definitely be much better and more stable.