Forward slip vs side slip versus crab landing…
If you land with your landing gear at an angle to the runway, you risk the sideways force collapsing them under the plane.
Always best to land with the plane aligned with the runway.
I have landed with strong steady crosswinds in a forward slip on approach according to the above diagram, which I was told was a crab landing, then switched to a side slip in order to keep the landing wheels aligned directly with the runway, albeit with plenty of rudder which meant that the upwind wheel touched down first, and the other main touching down second when speed/lift dropped sufficiently.
I have also done S turns on approach if I wanted to burn off speed/time/landing distance, but only when there was another plane ahead of me on the runway/approach.
Yes, this pair could have done S turns/weave back and forth to burn off speed/distance, but they may not have had the time/leisure to think it through and it may not have reduced their altitude fast enough.