I think this could be useful as a starting point for diagnostics - a cheaper, lower-power device massively lowers the barrier to entry to getting an MRI scan, even if it's not fully reliable. If it does find something, that's evidence a higher-quality scan is worth the resources. In short, use the worse device to take a quick look, if it finds anything, then take a closer look. If it doesn't find anything, carry on with the normal procedure.