Welcome to the forum,
I have been watching to see the replies to your question. I'm curious too about some of the certifications that are available for welders to take along with them and are recognized and accepted across the country.
I for one will test ALL welding applicants for production welding positions in our shop, regardless of the certifications they present during the interview. Anyone who is qualified/certified in our shop is welcomed to take those papers with them when they leave, but most places will retest these same people again before placing them into a production welding position.
I said all that to say this, many places will test you to the codes, materials, positions, thicknesses, and several other essentials that are relevant to the type work being performed in that shop.
You may or may not be wasting your money on certifications, it just depends on where and what you are trying to do. Remember, most codes have requirements that make the welder prove thier continuity hasn't lapsed for a six month period. In other words if you are between welding jobs and more than 6 months have past and you can't prove that you have been welding according to your certifications in the meantime, they are no longer any good.
I'm all for education and more of it can make you a better welder, so I'm not trying to discourage you in any way from furthering your welding education and some employers will be more receptive to giving you a shot at an interview if they see that you have been through some classes of a, formal type, welding education. But just "carrying papers" don't mean that you won't get tested again and again.
just a few thoughts to consider,
John Wright