Watch this video from a company that makes climbing gear:
https://dmmclimbing.com/Knowledge/September-2013/Slings-at-AnchorsSaying your gear doesn't need to be rated for falls if you are only canyoneering and rappelling is just not true. If things go sideways (and they will go sideways at some point) you can still pretty easily generate enough force to break your gear (and anchors), or your back. Even if your gear is brand new. I've found that canyoneers that are not also rock climbers have a poor understanding of this stuff.
One big problem is static links in the system. This includes static ropes (no stretch), static cord, and sewn static slings. These are all used to attach yourself to an anchor or other rigging/rope system. A falling body generates high forces much faster than you would imagine and theses static links transmit those forces straight to the linkages (carabiners, etc) and your body (spine, organs).
Because they are typically only rappelling, canyoneers often use static ropes (ie they don't stretch like normal climbing ropes). Even if you do use dynamic ropes that stretch, you are still using other static elements like cords and slings at various times like when attached to an anchor waiting to rappel. This disastrous situation can easily happen when clipping into a hanging anchor waiting to rappel and slipping with slack in the system.
From the video:
For an 80kg mass and 120cm dynema sling...
.....fall factor 1 falls (falling from the height of the anchor) generated 16kN.
.....fall factor 2 falls (falling from above the anchor) generated 27kN.
For some gear references:
... A typical anchor carabiner might be rated at 25kN (major axis, gate closed)
"Black Diamond Positron Screwgate Locking Carabiner"
https://www.rei.com/product/899070/black-diamond-positron-screwgate-locking-carabiner... and a dynema sling rated at 22kN
"Black Diamond 10mm Dynex Runner",
https://www.rei.com/product/899001/black-diamond-10mm-dynex-runnerSo as shown in the video, the above listed fall factor 2 breaks brand new gear. What if the carabiner got turned sideways? It's only good to 8kN now and broken in less than a fall factor 1.
..... and this all ignores the fact that you will have serious internal injuries (broken pelvis, busted organs, etc) at around a 12kN shock.
So ya, even canyoneering gear needs to be fall rated (and you need to be really careful to avoid static falls!!).