I would just say, can you afford to buy ANOTHER PA3X?
If not, protect it as well as you can possibly afford. Plan for the worst case scenario (LOL), not the best!
Me, I'd go for one of those rigid Gator type cases at the very least.
A fairly common scenario might be, can your keyboard case stand up to someone dropping one of your speakers on it? It can happen (trust me!). If that is enough to go through most soft, semi-soft and single ply wood cases, go a bit tougher.
Bottom line is, will your insurance replace your PA3X if YOU damage it? And will they insure your next one affordably? If not, don't skimp on the case!
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An arranger is just a tool. What matters is what you build with it..!