Full scan. Still absurd to what we've come to to think this is tolerable.
There's a lot more to value than the price.
It's not a datastore to power a crud app, or anything requiring frequent queries, but it's a great place to stash gobs of logs that you may need to query at some point. Or it's great for serverless batch workloads and is often cheaper in both time and money than firing up spark clusters or something similar to do the work.
Quite frankly, it's awesome. But sure, they do use it as a tool for lock-in, and for some cases it would be prohibitively expensive.
I find 50c to read 100GB from disk, do useful work on it (including running javascript code or ML models if you are so inclined) and returning a result in seconds... pretty damn incredible.