Moveable chords have no open positions. Blues guitar playing uses moveable chord forms as much as any other type of guitar style, including the common 6th-string root chords shown here:
Moveable chords with the root on the 6th string.
Common moveable chords rooted on the 5th string include these:
Moveable chords with the root on the 5th string.
Some more complex moveable 5th-string-root chords.