I'm glad you found one flowthrough that worked, I guess that proves that they're worthwhile. The majority of pilots who have some sort of flowthrough agreement to a major airline are still sitting at a regional, many for 10+ years. Overall I think they are worthless and the pilot groups should never accept them as a carrot in their contract negotiations.

If there is a pilot shortage you won't need contractual language to make it to a major. if there is no pilot shortage you're not making it to a major whether you have a "flowthrough" or not. It's just another set of the emperor's clothes that managements keep selling us and we keep buying.