It’s my opinion (as an infrastructure type) that centralised binary logging is an absolute necessity above 20 instances.
But that leaves out every person with a laptop, or those people with a very low volume of little instances.
Structured logging is difficult, that’s why logstash is so flexible about input and conversions. And I think that was the impetus for systemd’s journals; to log structurally.
However. The parent is wrong if he thinks decisions should be made under low disk conditions. Having a rotate rule to keep your sliding window of logs to a certain size is fine. But your servers (and laptops, and desktops) should not be taking arbitrary decisions based on this kind of condition.