From a range of conversations that I've had, I feel that the case for at least some families is that they are wanting the absolute very best for their child, and so they are willing to try anything to achieve the best outcomes - irrespective of the type of intervention. Perhaps clinicians can feed into the idea of 'therapy, therapy, therapy' too, where families feel that 'more is always better' and so every hour of every week is filled with therapy - again irrespective of the intervention content or evidence base.
Sometimes non-evidence based interventions also look more fancy or specialised and this might have a sub-conscious impact on an individual's perception of how valuable a particular approach is - hands-off therapies can look unimpressive!
Sometimes non-evidence based interventions also look more fancy or specialised and this might have a sub-conscious impact on an individual's perception of how valuable a particular approach is - hands-off therapies can look unimpressive!