CSV is a pretty terrible format for storing and transmitting data: it only supports string types, the escaping rules are poorly understood, and it can only model a single flat table.
CSV files have a single order and no support for indexes. Even if you sort your CSV on one or more interesting columns and use binary search to locate an interesting range, you can still only do this along a single dimension, any remaining queries must scan the entire file. You'd also have to write all the code for this yourself. SQLite is a much better solution
