A loader is best at scooping up loose material. If you try to dig with it, especially with rubber tires, it will bite into the dirt, squash down the tires, and then try to dig even deeper, which will stop your machine if the dirt is somewhat hard, or at best, will lead to a very uneven surface if you can dig out a few chunks at a time. Back blading (scraping backward with the bucket in a fully dumped position) will give you a little more control, but it is still not easy if you have hard or rocky ground.
PILOON amd RBA50 mentioned using teeth, and those would make a huge difference. A toothed box blade might work better than a loader alone for your application, and would be cheaper than a backhoe.
On the other hand, if your future patio isn't too large, say 12' x 20' or smaller, and your soil isn't rock hard clay with a lot of rocks in it, I'd say go for it. If you're not sure, take a shovel and dig a hole. See what you get into. I have a backhoe, but for an area that size I'd probably first try to use the loader rather than mounting the backhoe. You should be able to get the first 8 or 9 inches of turf off without much trouble. Don't know your soil, so I can't speculate about the next 9 inches!