What a waste of time and money!
Obviously it’s not, or they wouldn’t do it- it pays off for them in one way or another, and if it were more cost and time effective to do it themselves then why is it that they don’t?
As far as hydroforming making no difference other than making them look swoopy, I don’t think it’s as simple as that (although I’m sure there is an element of that- either cos they look dated without it, or to give a design cue or brand identity). Having the right amount of material in the right places is handy, which is why tubes are butted instead of just being uniform and carbon is so useful.