In the early 2000s, Dyneema was a breakthrough lifeline material. It is as strong as steel and much lighter, inexpensive, simple to install (at least it seemed that way), low stretch, UV resistant, and chafe resistant. World Sailing accepted it for racing. And then in 2016, World Sailing changed their rules, restricting Dymeena lifelines to inshore and multihull racing. Several boats had broken lower lifelines. It turned out that when rail meat leans over bare stainless wire lifelines, the rocking wire forms sharp burrs inside the stanchion holes, and when you switch to Dyneema and hang rail meat on them again, the burrs can saw right through Dyneema lifelines. Another risk, recognized by super maxis, such as Comanche, was that the heat generated by a spinnaker sheet running across a lifeline at high speed could melt it. For the boats we sail we assumed this was only theoretical.
After this discussion, why use it at all!!
Because there are applications (most cascade purchases, for example) where Dyneema outperforms anything else, including steel cable. There can also be a tendency to use Dyneema for everything, which is wrong.
Like anything, design and material selection go hand in hand.
Spectra is the default line choice for modern skydiving parachutes. Spectra linesets are typically replaced every 200-300 jumps because friction heating and the resulting contraction pull the sets out of trim. It’s a great material, but you do need to be low-key paranoid about it in applications with significant friction.