A riveted boat doesn't stay together well in conditions like this:
https://www.youtube.com/watch?v=tBbRz7E_OE4
Speaking from experience. I live in an area where these hunting areas are like this, and this is why welded boats are the ONLY way to go, especially if you're rough on them like Freddy is. I frequent a local lake (fishing only) that is FULL of submerged trees, stumps, logs, a few rocks, mud, etc. Those are another reason I won't own another riveted boat unless it's cheap. It's all I had in the past. And I fought leaky rivets, seemed like constantly. Most of the time there is no way to avoid hitting a stump or two, even idling around. They are many times a few inches under the surface the the water is murky, so you cannot see them, but you sure can feel 'em. Really a potentially dangerous situation; most that fish the lake frequently know to go slow. Always a new guy in an expensive bass boat trying to run a boat trail at 30+ mph and it's not uncommon to hear the tell-tale sound of an outboard out of the water, when they hit a stump or tree or log.
Another plus to a welded boat (at least a good one) is resale value. Much high than a riveted boat; generally speaking. Especially in this area. A 1542 riveted hull is really lucky to fetch $800. A 1542 welded hull, hard to find one under $2000. Supply and demand. Everyone wants welded. Could be just this area, because of the types of waters we have and the hunting in flooded timber being so popular.
MIG welds. Many of the cheaper boats are all MIG welded because it's faster than TIG welding. But, MIG/spoolgun with aluminum isn't the best option. 2 reasons. One, it's a little harder to get a GOOD weldment, and two, it's fast (cheap), just sticking two metals together is all it's doing. A TIG weld on the other hand is much slower process and for that reason, generally speaking, the weld is of much better quality both from a structural standpoint and a cosmetic standpoint. One neat thing about TIG process is that if for some reason a weld is not quite right, it can sometimes be "fixed" pretty easy, where a MIG weld would need to be sanded/ground and then re-welded. Some of the weldbilt's are fully MIG welded. Most of the War Eagle's are tig'd structurally and then some of the non-structural stuff is mig'd. Then I've also seen some other brands that were FULLY TIG welded, they're expensive but you don't ever have to worry about 'em.
Weld cracking is mostly due to flex. Aluminum will flex some but it doesn't like to flex a lot before it cracks or breaks. I've seen WAY more cracked transoms on riveted boats than on welded boats. Probably a 50:1 ratio if I had to guess. One reason I am guessing is that welded boats are thicker material, therefore they flex a LOT less. The ones I had (riveted boats) were always cracked somewhere. But they were always made out of tin foil, like .063" maybe thinner (never measured). And I would sand/grind and re-weld them as needed. And buck the loose rivets which was a yearly project it seemed like. I am averaging 30-50 hours a year boating time, so I'm not out all the time but I don't sit around the house either. Actually before I bought the war eagle, it was not bothersome to have a gallon or two of water in the boat after fishing for 4 hours. I considered it normal for a riveted boat. When I got the new one, it didn't leak a single drop. The second outing with it, I purposely stayed out from daylight until dusk to see how much water it took on. Not a single drop. It felt weird.
I had bought only 2 brand new hulls in my lifetime. One was an Alumacraft 1542, the other my current war eagle. The first outing in the alumacraft (riveted), I run it up on a stump at idle speed, so under 2 mph (9.9 evinrude). Did a great job of putting a nice dent in the bottom of the boat, which I had to beat out when I got home. Thin material. Have hit these obstacles with the current boat a thousand times probably in the 4 years I've had it, and there is not a single dent in the bottom. Not one. .100" material. A few scratches, yes, mostly from concrete ramp damage from launching myself and no dock to tie up to, but no dents at all.