One reason is the lack of native support for columnar storage (though an open source third-party extension exists: https://github.com/citusdata/cstore_fdw https

One reason is the lack of native support for columnar storage (though an open source third-party extension exists: https://github.com/citusdata/cstore_fdw https://github.com/citusdata/cstore_fdw) The need to manually update clustered indexes, and the fact that an exclusive lock is needed to do so, is also annoying.