Since you can look at it either way in that regard, it's
reasonable to have the option that's best for most users as the
default. As I see it, that's to enable tmpfs for /tmp .
Given a choice between "works for everyone" and "works well for most,
but fails in obscure ways for some", I'll choose the former.
I find it amusing that this argument is going for the "screw some of
the users so others are happy" way, but the reboot-to-update argument
is going the opposite, the "must always work for everyone no matter
how painful" way.