As you may know co-washing (conditioner washing) is the perfect way to add moisture without you having to do a full wash. As you also may know co-washing only involve using conditioner and conditioners are not made to cleanse the scalp which is important. So as with anything good there are some bad components attach to it as well.
This video explores the pros and cons of co-washing which works great for some people but not others. The difference, I believe, is in lifestyle, and your hair type plays a role as well. Many naturals do daily co-wash as their regimen and achieve great results, while others complain that it leaves them with brittle and dry hair, not the desired result.
Here is the video: