there's a difference between high CTR and high conversion..
It would have been interesting to see a measurable goal (downloads, newsletter signups, watch a 3 minute video... something measurable) and how the conversions were across the two ads.
The MS Paint ad still may have more total conversions but it would be interesting to see how the cost per conversion compares. If both cost per conversions are within budget, then by all means go full speed ahead with MS Paint.