[namibj]

Err, you can use CC-BY-NC the same as AGPL can be used for semi-commercial software like CockroachDB et al. Yes, a plain CC-0 or CC-BY makes it hard to sell licenses, though they are still possible, due to not being able to make it look endorsed by the original creator, which is somewhat hard in e.g. submarine ads, like those where billboards show something you don't understand for a few weeks/months, followed by a reveal that links the brand to the campaign. There are probably other usecases that are blocked/made hard by CC-BY alone, without even going to CC-BY-NC.