many packages now require jre but not jdk. notably, chromium requires jre if USE=closure-compile (on by default). if jdk is required in the same emerge command (example: DEPEND=jdk, RDEPEND=jre), it will automatically be pulled in and openjdk-jre-bin will not be installed. moreover, if you install something requiring virtual/jre, and then install virtual/jdk, then openjdk-jre-bin will automatically be removed with depclean. this also does not cause unnecessary flip-flopping: if virtual/jdk is already installed, then portage will not additionally install openjdk-jre-bin. therefore, I think it is in most users' interest to use openjdk-jre-bin by default.
no. most users prefer non-bin jdk instead of binary jre. jre does not make a lot of sense honestly. and if you don't clean bdeps it will not be removed by depclean. closing.
*your* explanation "does not make a lot of sense". if users prefer non-bin jdk, then why the hell does virtual/jdk (*not jre!*) prefer bin? and don't be so high and mighty. if you want to talk about "not making sense", then why the hell does openjdk ebuild have this nonsense: einfo "Creating the Class Data Sharing archives and disabling usage tracking" "${ddest}/bin/java" -server -Xshare:dump -Djdk.disableLastUsageTracking this jdk.disableLastUsageTracking parameter controls oracle java usage tracker, which is not implemented in openjdk. it also doesn't work, because it would need to be set on every java invocation. furthermore, java usage tracker also needs to be explicitly installed and enabled by the administrator, so even if this worked, it would contradict the administrator's explicit request. *that's* nonsense.
I, as a regular user, prefer binary jre if jdk is not necessary.
