Running ads on Instagram or Facebook to promote your YouTube channel can be a good idea to increase visibility, generate more views, and potentially gain new subscribers. However, the success of this strategy depends on several factors, such as the quality of your content, the targeting of your ads, and the effectiveness of your ad campaign.
However, it's important to track your results and adjust your strategy as needed to ensure that you are getting the best return on your investment, if not change your strategy.