I don't think people use it for reproducible environments on their own machines the same way Docker is sometimes used, I've mostly encountered it in academic compute clusters as a way to install the libraries/languages you're using onto the cluster in an easy to remove way. So it's popular in HPC clusters specifically and not really tied to a field of research beyond that.

Re science: yes and no. Meaning: the old way of compiling programs from sources on HPC systems while not dead is becoming rare. I can only speak about bioinformatics: the majority of programs one can get up and running in no time using either conda environments or apptainer containers. It may take few weeks for the brand new shiny version to get packaged by the maintainers, but this is seldom the problem.

Even if you want to compile some program you will save yourself the time and frustration using either conda env or a container with a required toolchain/libraries. Even on a box with root access you need to avoid conflicting system wide installed library versions where program A requires lib version X and program B lib version Y.

Used to be called “Singularity”