> Part of the reason for floatation devices is a transitionary measure to get them more used to and practiced in "preswimming" while participating and not simply wading or pool side clinging.

The reason for worn (handheld is a different story) flotation devices other than lifevests is to sell flotation devices; I've never found anyone who teaches swimming to children (or adults, but that's not the market for them anyway) that uses them, advises using them, or considers them anything other than a safety hazard.

If you want to get a kid used to “preswimming”, which as I've seen it is actually something mostly done with infants and toddlers (older nonswimmers usually seem to go straight from wall exercises to supervised short swimming with knowledgeable teachers) it's best to do it with an adult holding them, except for extremely brief transitions.