If you're in the habit of worrying about persistent malware on your device, "regular restarts" are one of the best things you can do.
Much of the low interaction malware is only persistent in memory, so a reboot will clear it until they get their claws back into you. Depending on what the attack path is, that may take some while - and using those attacks is still somewhat risky. "Having to re-pwn a phone every 6 hours" is a lot more risky to an attacker than "someone who never reboots their phone and never updates it."
Yes. Also, regularly doing a factory reset is another good hygiene habit to have, this will clear the more rare but persistent forms of malware, often brought on board by legitimate software you installed a long time ago but no longer use.
