I've not used the 3M product or any adhesive structurally, but I have used a similar product by Sika to bond sheet metal (skin) on a 40' BB. It worked great. Properly applied, it has been proven to equal or surpass welding. The only question about these new technologies is long term durability. How will they be holding 10-20-30 years from now? But combined with rivets, it should be more than adequate.
Note: OEM applications have been around for close to 20 years now on autos, trucks, rail cars and aircraft. So far the high-tech adhesives have proven extremely tough, strong and vibration resistant since they retain a measure of flexibility. But...as noted above...the prep & application process is critical. Do it absolutely right or don't do it at all.