and somewhere in all of this is dangerousness - just flying along having traded speed, performance, stall speed, to see what happens - else why fly in that config?
I don`t know why ... anyone would want to fly with a trade off rather than go for a perf.
Operationally, a pilot might choose heavy weight over performance, if that heavy weight were to be ferry flight which could not be accomplished at all within the regular weight. Otherwise, the modification of a landplane to be a skiplane, floatplane or amphibian will increase weight, and decrease performance, but is an accepted compromise, based upon increased utility. A C 172 landplane owner, who is entirely content to carry two people and bags might choose a 182 amphibian to maintain that capability, as the 172 amphibian might not have full fuel capability with that load. But neither Cessna is achieving the performance that it would have as a wheelplane.
to see what happens
Test pilots aside, no pilot is flying within the limitations of a certified aircraft to "see what happens". The data is there, and design compliance has been demonstrated for the proposed weight, with stated power.