No, that's different. Cooking sprays usually include Soy lecithin, which can cook on (if you don't wash it off) and forms a sticky brown residue. The polymerized oil is slippery.
The residue issue is more pronounced in thick/dark pans like cast iron that retain heat for a long time -- unless you clean them immediately, the residue cooks on. If you cook some eggs, eat, and go back to clean your cast-iron pan, the oil will have been cooked on.
The solution for this use case is to use something like the "Misto", which is a spray pump that lets you spray plain oil on a pan.
If you're not cleaning off the overspray, you'll definitely get sticky brown residue from oil. Oil is only slippery after it's fully polymerized. If it's partially polymerized, it's a sticky mess. Oil on the sides of the pan will generally not fully polymerize without a cycle in the oven because there isn't enough heat being applied.
The residue issue is more pronounced in thick/dark pans like cast iron that retain heat for a long time -- unless you clean them immediately, the residue cooks on. If you cook some eggs, eat, and go back to clean your cast-iron pan, the oil will have been cooked on.
The solution for this use case is to use something like the "Misto", which is a spray pump that lets you spray plain oil on a pan.