OK, the worst case with this is that you'll have to replace it eventually, probably sooner rather than later. Since it's working though split, either the inner liner is intact and holding it together, or you have a short spiral brake type housing which doesn't depend on the cover for support.

Either way there's no likely untoward consequences from leaving this as is. Bad housing cannot cause the RD to go into the spokes, that's done with a correctly inner limit screw. Since the cable pulls the RD inward against the spring a total cable failure of any type will cause the RD to shift outward and have you riding home in high.

So yes it's die and you'll have to replace it, but don't lose anything by waiting until you have no choice.