Some systems the logs are journaled records for the business or are discoverable artifacts for compliance. In highly secure environments logs are not only durable but measures are taken to fingerprint them and their ordering (like ratchet hashing) to ensure integrity is invariant.
I would note that using disk based logging is generally harmful in these situations IMO. Network based logging is less likely to cause blocking at some OS level or other sorts of jitter that’s harder to mask. Typically I develop logging as an in memory thing that offloads to a remote service over the network. The durability of the memory store can be an issue in highly sensitive workloads, and you’ll want to do synchronous disk IO for that case to ensure durability and consistent time budgets, but for almost all application disk less logging is preferable.