Why is canola oil so helpful?
High smoke point. Take a hard look at the "health" benefits, however, and you may decide that the difference in smoke point isn't worth it. Personally, I prefer high oleic safflower oil.
OH yeah...the fishy smell of canola at high frying temps. Bothers me. Peanut oil is better (but then you have to have to worry allergy in a commercial setting)
Love the third sentence of your first paragraph! And agree with all the rest.
Canola oil is one of those mostly flavorless oils (unless it's rancid, in which case it's pretty disgusting, but that's true of any rancid oil) that can be nice to use when cooking dishes where you don't want the flavor of olive oil and need something with a higher smoke point. And frankly, olive oil has become overused--just like any oil, olive oil is not appropriate for all uses in the kitchen.
Unless you really go through a lot of neutral-tasting oil, don't buy oils in large quantities. I know it's tempting to get the huge bottles and save a little money, but you probably won't be able to use it before it goes off.
We like to keep around small bottles of different types of oil for different applications--a really nice bottle of evoo with a pronounced flavor (for finishing dishes, or where you really want to taste the fruitiness of the oil), a decent but relatively inexpensive olive oil (CA Olive Ranch is good--use for salad dressings or low-heat applications), safflower oil (for high-heat applications and baking recipes that call for oil that aren't olive oil specific), and coconut oil (frying, and sometimes vegan baking where a semi-solid fat is nice).
To make matters more wonderfully complex, we prefer to make some dishes with clarified butter or butter, and sometimes lard, bacon drippings, or duck fat. Each of these oils has a wonderful flavor, and as Chef Ono mentioned above, saturated fats are oh so satisfying even in small doses.
Essentially, the "heart-healthy" label means nothing. There are all sorts of factors in determining heart health for each individual--genetics, diet, exercise, etc. Eating butter or lard on occasion is not necessarily any more harmful or less harmful than canola oil. There are those who would argue that saturated animal fats are better for you. Personally, I refuse to make claims about how healthy any given thing is. You have to look at your diet holistically to determine where the individual parts fit in. We should also ask ourselves hard questions about where these oils come from and the processes involved in producing them (http://wellnessmama.com/2193/why-you-should-never-eat-vegetable-oil-or-margarine/)--the author of this article is clearly biased against vegetable oils, so take that into account, but her description of the process is correct. In truth, vegetable oils are highly processed foods, which may matter to you and it may not.
Bottom line--no need to confine yourself to using one oil for any and all applications. Learn about different oils and how to use them, and you'll be much happier with your cooking. They're tools not dissimilar to spatulas and pans--you need the right one for each dish.