Protective gear is part of every motorcyclist’s consideration. How riders apply that consideration varies wildly; you’ve got some riders who want nothing to do with it (including helmets), and other riders who go full ATGATT (All The Gear, All The Time — pronounced at-gat). Should you choose to wear any protective gear, you'd expect that gear to perform in the case of an accident, yeah?
Based on my experience and informal education, gear should provide two things: impact protection and abrasion protection. During a ride, if you unexpectedly separate from your bike you will (one) make contact with the ground and (two) keep moving along that ground until friction brings you to a stop or (three) you hit something.
Impact protection helps with (one). Some offs bring your body to the ground harder than others. Here's hoping your off is a low side.
Abrasion protection helps with (two). Whether you’re sliding at 25-80 MPH on asphalt or dirt, you certainly want something between your skin and the ground. I don't recommend you research the examples of what happens to skin when it slides across the pavement at high speed. Just thinking about it should be enough to clarify why this kind of protection is important.
And impact protection helps again if (three) you're unlucky enough to be brought to an abrupt stop by a curb, other vehicle, ...
When you shop for motorcycle gear, you'll be presented with tons of considerations. Price, style, fit, comfort. All of those considerations are important. You want to find something you can afford that looks good, fits good, and that you can stand riding in for hours at a time. But before you commit, remember to look the product over through the protection lens:
(one) Will this thing help when I slam into the ground? Does it have knee/hip/elbow/shoulder pads?
(two) Will material tear as I slide across the asphalt? Will it transfer heat directly to my skin?