@rosborne979,
rosborne979-
I think so.
If the terms of the voucher provide that it must be accepted by the school as full payment of the tuition, then it is available for use by all the students. It makes schools affordable that previously were not affordable.
If the terms of the voucher provide that it may be accepted as partial payment of the tuition, then it may help rich families pay for expensive schools, while excluding the poor.