chroot was (is?) the recommended way of installing gentoo which is pedagogical.
There are various handy (chroot) techniques that are probably considered "old school" now. For example, having a "rescue partition" which can be booted into remotely, and from there reinstall or repair the "main os". This is necessary when repartitioning remotely, for example.
That’s still how most Linux OS installers install. They just do that for you.
It’s still used for recovery but recovery partitions have kinda gone out of fashion as the ability to consistently boot has gotten better. Additionally, thumb drives and net boot make the partition a little less necessary.
There are various handy (chroot) techniques that are probably considered "old school" now. For example, having a "rescue partition" which can be booted into remotely, and from there reinstall or repair the "main os". This is necessary when repartitioning remotely, for example.