It appears as though there are also holes in the bottom of the rockers as well.
With a unibody vehicle, the rockers are structural members of the unit, and the cross braces are what keeps the body from folding up in a crash, they add support for the floor pan. Just going from the pictures given, I would suspect that in the event of a side impact crash, that side would crush in pretty easily if that corner was the point of impact, it probably is around 50% of the original strength, which wasn't much to start with. The actual condition of the floor pan could alter that percentage some, but I suspect they are probably not very good either, that 50% may be generous. That stated, if the weak point is not the point of impact, how it effects the crash outcome may be of very little importance.
As for being safe, that is a matter of opinion. The Jeep has been around this many years and doesn't appear to have been involved a side crash, and the odds are pretty good it probably won't be in one. Baring any crash or a trip through the ditch, the Jeep will probably rust out to the point you no longer want to drive it, or it may suffer from a mechanical failure that will end its usefulness. I guess it depends on what your threshold of concern is from a safety aspect.
Up until I retired in Oct, I used to fix this kind of stuff. Gene
