Use Postgres as a column store by creating one table per column

Is it efficient to use Postgres as a column store by creating one table per
column?

I would query it with something like `[...] UNION SELECT value AS <table>
FROM <table> WHERE value = <value> UNION [...]` to build a row.

I'm thinking since Postgres stores tables in continuous blocks of 16MB each
(I think that's the default page size?) I would get efficient reads and
with parallel queries I could benefit from multiple cores.

Thanks!

Best,
Lev