i ask because new products come out. J boats is using this on their new boats, among others. it has both high strength and flexation. i know others use sitaflex or 5200, but i don't think i would go that route. and yes, the product would supossedly be a permanent solution or nearly so, as in impossible to get apart without huge damage to other pieces.
i guess the real question is somewhat related to hard joint vs flex joint. perhaps a hard joint needs a greater surface area. this would make sense to me.
Most boat builders today use Plexus adhesives but they make a number of them. The stuff you gave a link to is usually what they use for grid pans and liners to adhere them to the hull and it has quite low elongation when compared to other products.
None of this stuff will work well if the two mating surfaces are not 100% clean. This will be nearly impossible with an inward flange. You can clean the exterior overlap edge and lay a bead of Sika 291 or 3M 4200 along it then let it cure and re-bed the toe rail over it.
Short of lifting the deck off the hull by 6" to clean it and re-bed it any attempt at re-sealing, short of fiberglass cloth and epoxy, will be a "cross your fingers approach". Some builders used Dolfinite bedding compound which is closer to plumbers putty and not really thick enough or aggressive enough for a hull/deck..
It may just be the bolts leaking and you could always remove them one at a time and re-bed them too.
At least yours can come apart if you have to. My buddies boat was sealed with 5200
, and is leaking, so he's rather screwed as there is no getting it apart at this time. It's no fun potentially destroying 35+ feet of aluminum toe rail to re-bed it. Sadly they don't even begin to make Anti-Bond in large enough cans to begin tackling this job...