Depending on your performance requirements extra milliseconds of roundtrip to the externalized queue may be too long of a wait. Or you may simply not care enough for an extra piece of infrastructure that you'd need to support, and maybe this is good enough.
It's is all about trade offs, no solution fits all use cases.
its always about tradeoffs. one nice compromise position here is that the log is always consistent, so you don't need to wait at all if you don't mind losing the tail on a crash.
