should `dist-upgrade` be followed with a reboot?
Following a periodic, in my case weekly, run of:
apt-get update
apt-get dist-upgrade
is there much benefit from rebooting?
You only need to reboot if Ubuntu tells you to, e.g. when a new kernel got installed. (It's even possible to circumvent those reboots via e.g. ksplice, which applies updates to the running kernel.) Otherwise there is no benefit from it. Restarting the specific application or a log out and log in often is enough to get all the benefits from updates.