I understand due to unusual advertising bouncing around the Internet
regarding sponsons, this is quite an emotional topic.
Before any advice

I have sponsons. I do not sell them. I can capsize my kayak with
sponsons attached. This takes more effort than without these devices.
As long as I do my eskimo roll correct, with the sponsons attached,
I can capsize and roll up consistently on my strong or left side (no
wind or waves). I can almost make the roll up on my weaker or right
side. I cannot stand up in the kayak with the sponsons, although with
practice I could. And with practice, I could stand up in the kayak
without sponsons.

The sponsons offer some measure of safety. For me, sponsons are a
great way to perfect my eskimo roll in a sea kayak. I have to do
everything correct to roll back up with my sea kayak with the sponsons
attached. I think good bracing technique and an eskimo roll are
better techniques.

To use a bicycle comparison, sponsons offer less safety than training
wheels on a bicycle. When much younger, I had great difficulty
tipping over a bicycle with training wheels (would have to be going
"fast" around a curve). I can roll a kayak with sponsons (see above).

I believe the safety is less than advertised. The sponsons (I bought
used) came with a serious product defect. There are plastic clips.
Upon my testing using eyepads on a kayak, one or both of these clips
came off the eyepad (in a real world situation, the sponson would had
blown away). I replaced the plastic clips with chain links. This
replacement solved the problem of the sponsons detaching from the
kayak. I was quite annoyed at this defect. The end of the inflation
tube (which connects to the sponson) also came off during "sea trials"
and the sponson deflated. A little epoxy fixed that problem.

I will still consider the use of sponsons as a last ditch safety
device (swamped canoe, in a storm). There is the good question of how
did I end up on the water in those conditions. The kayak or canoe is
somewhat more stable. I have not tested my boats with sponsons in two
to four foot waves while traveling parallel to the waves. This is
next on the list. I will also use the sponsons with a downwind sail
as they offer more stability with both the fla****er canoe and sea
kayak.

And yes, they are view with disdain by many and much hated on Internet
newsgroups - (like bicycling around with training wheels).

End