Yes, I would avoid the ski tubes just because they have a good chance of not being put back together correctly when TSA opens to inspect. I have seen at least 4-5 people posting here about seeing their tube and ski gear showing up on the other end in pieces. And as noted, the tube is not going to help in the most extreme damage scenarios that will crush anything.
I picked up a ski bag and boot bag set at Sam's club many years ago for something like $20. The bag is padded, has a rigid bottom along the lower 1/3 of it's length, with wheels and skids. It has held up well over many years. In fact, here it is after returning from Utah last evening:
I like soft bags because I can surround the skis with other crap, including spare clothes (or dirty clothes on the way home), snacks, gloves, avy beacon and probe, etc. Basically anything that doesn't fit into my main suitcase and boot bag (both are carry-ons so that I can still ski even if my ski bag gets lost in transit). I even put my helmet in that ski bag -- see the bulge up at the front. It fits over the tips of the skis, with some padding in between to protect the helmet from the ski tips.
I bought a roll of sill insulation, which is a blue, pink, or white closed cell foam about 1/4" thick and 6" wide, in a 50 foot roll. Carpenters use it between the foundation and sill plate when framing houses. I put a strip between the skis before strapping them together, and use it to wrap the tips and tails. I also put some padding around the heel pieces and brakes to prevent any incidental contact from bending the brakes. Once I stuff everything else in there, the skis are pretty well isolated. A short piece of garden hose bent in a "V" goes over the tips of my poles to keep the tips together and prevent them from punching through anything (they are sharp).