When I raced 4X a few years ago I more or less locked out my mtb forks so they didn't bounce at all, I couldnt believe how sloppy my gates were with any suspention. The only benifit I could get from them was if I over jumped a landing my wrists wouldnt break, or pre-loading before a double to get a bit more pop. The only track I think I needed suspention was fort bill, big, bad drops there.
Sorry, I don't think BMX's should have any suspention at all and I dont believe with the smoothness of a BMX tracks you get any help from it. Not to mention they look terrible. Super rigid wheels with loads of psi is what makes you go fast imo.
If they were of any benifit at all they would still be being used for racing now, as far as I know theres nothing stopping you, shit you can even use gears and clips if you must......
Those who like them, fair play, it's all good, if we all liked the same things this would be a very boring message board!!
Oh and elastomer forks squeek, remember those old Pro-flex mtb's, you could hear them coming from miles away.