These exercises were developed by Kegel. Hence the name. They have been in use for different purposes. It ranges from tighter pelvic muscles to prevent urinary incontinence in post partum mothers to premature ejaculation.
All in all it is a technique in which the pelvic muscles are exercised. This is technique to have your pelvic muscles tight. This surely helps anorectal diaphragm.
We can safely say due to prevalence of the technique that it should work. But the real question is if it works in reality also? The answer is not pretty straightforward. But an Ebook called Ejaculation Trainer might shade some light on it. So please take a look.