The only issue I can see is that they are slippery so you might want to put a runner over them for safety sake.

Those type of flooring tiles do not usually come with the necessary trim pieces necessary to edge the stairs such as corners and bullnose pieces, so they could not be used on the treads. However they can be used on the stair risers.

Yes you can use any tile on stairs. Use a tile with texture for traction. There are plenty of wood look tiles that offer different textures.

I know Build Direct isn't popular here, but I ordered sample wood look tiles from them and they didn't seem to be slippery at all. The do have a texture to them, maybe that's why.

One concern with putting the tile on the steps is the finished edge. You will need a product called Reno-Step from Schlueter systems. It will hide the raw cut edge of the tile. Although these are metal they are available in an array of colors. This may be a bit more "industrial" looking than you want. Also make sure the installer is putting concrete underlayment on them as well or you will get cracks over time and it can also cause grout issues. When the concrete board isn't used the moisture of the mortar needed to hold the tile in place gets absorbed into the wood step and therefore the tile isn't adhered properly. And tile, no matter how textured it is, becomes slick when wet. Keep in mind anything that falls on it will break, not to mention it will be hard to clean if it has too much texture.

You may consider a nice short patterned carpet instead of the tile. It would wear like iron and look pretty too. www.tuftex.com has some fabulous choices. We have one of these as our cover photo on our page if you want to see an end result. Good luck with your project and Happy Houzzing!!

Adding tiles to stair treads can have issues. Sometimes the treads aren't rigid enough to handle tiles. The "flex" that a tread goes through when stepped on can be too much for mortar/groute = tiles will pop. To prevent this, you need to add rigidity to the tread (more plywood = more expensive).

When working with a textured tile the slip rate is reduced...but not eliminated. Imagine a stocking foot in the middle of the night...slip/bang/boom. The other complaints from homeowners who added tile/stone to their stairs = they are REALLY LOUD; they are really cold.

Many people have removed the tiles on their stairs shortly after installation (yep...double the fun and tripple the price). A carpet runner that has tiles on the edge to offer continuity might be the best option.

You would need to use cement board to prep the surfaces of the threads and risers, not plywood, for maximum bonding and strength.
Personally, I'm not in favor of solid tiled staircases. We prefer to install tile on the risers and have solid wood treads. This route will allow you to bring some personality to the area.