We are not window treatment people either, but have started to add some as we've reno'd/decorated a few of the rooms in our house; two bathrooms and our office. They really do help to finish off a room. That said, we're not covering our kitchen bow window, or the DR bow window, though I might consider something for the DR window at some point--just for the window panes themselves, not to cover the whole bow-unit. We used Hunter Douglas' Designer Screen Shades in the Roman Shade style (ours are mounted inside the frames becuase of our window style/frame depth). The shades are very clean-lined and range in sheerness. With the sheerer weaves/fabrics, you can see outside with them down and they allow a lot of light in.

I recently bought a product called Veilish. It’s a window film made with fabric material. It’s semi-transparent, so it can provide indoor privacy without blocking the view outdoors. The best thing is that it is self-adhesive, and it can be installed and removed easily, so you don’t need an installation expert. I think you will definitely be satisfied with this product.

Since you have the cranks on the windows and need access to them, I wouldn't put anything there. Valances can be old fashioned and your windows are more contemporary. If I didn't need privacy, I would forego window treatments. The views are nice, but if you don't want to see the deck and its furnishings, try an inside mounted semi-sheer cafe curtain on the tall window. That still allows a view of the trees, but will block the deck and railings from sight. Add color to the kitchen with some colorful hand towels, pot holders, crocks/cookie jars/canisters, a kettle or small appliance. If you limit the items to a few decorative accessories, you can change them out when you feel the mood or the seasons change. Pops of orange A bit of lemon Turquoise

Matchstick blinds would be nice. Those don't hang to the floor and would not have to match the other curtains. We have a similar window in our bedroom but it's an octogon. We use drapes to the floor on that window that match the other drapes in the room...the french doors and another window all have drapes to the floor. It looks good.