Use what is more comfortable for you.
If you make a concerted effort to use the view finder, you will get used to it and will probably have a hard time going back to live view if you are an avid shootist.
Live view has so many issues that people who want to be efficient will use the view finder, be it optical or EVF. For a professional, time is money and time (wasted) can cost you that critical shot. For me, when I use my point & shoot camera with live view, it's really hard to compose the image outdoors in bright light because the live view image is washed out. You'll miss the tree branch coming out of someone's ear in that situation.
Another annoying thing about live view is when composing the image, holding a camera at arms length means the camera is far away from the rotation axis (your body). This means objects will move in relation to each other, akin to parallax.
When shooting fast action, like sports or birds, it's hard to follow the moving action with live view (arms extended, hard to see in daylight, and screen blanking out between shots).
For me, battery life is very important since I take extended trips (2 to 4 weeks) out in the bush with no chance to charge batteries. Live view eats batteries. I can get over 1000 shots on a single battery charge using the optical viewfinder.
Put a big lens on your camera and see how long you last holding your arms out when shooting live view. My long lens weighs 5 pounds and I use it hand-held sometimes. When using this lens, I'm stalking critters which means I may be scoping around for an extended time waiting to get the right shot. If I was to use live view, my batteries would be dead before I got a shot off.
That said, I do use live view when appropriate, which is product shooting. I'm indoors and live view allows me to do critical focusing since you can get 100% magnification on the back LCD screen. Very handy for macro shooting.
There's also another plus to live view. If you have a lens with bad spherical aberration (focus shift), live view will focus at the aperture your camera is set to. Optical viewfinder always focuses with the aperture set to maximum (lowest f-number).