The phrase "confusing to use" is correct and usable in written English.
You can use it in a variety of situations to describe something as difficult or hard to understand. For example, "The software was confusing to use and presented a steep learning curve for new users."
These sites can be confusing to use at first.
But other changes meant to make the design easier can be confusing to use.
But many customers have complained that the phones can be confusing to use.
Because digital technology is so flexible -- programmable, in computing terms -- digital products, if not wisely designed, can be maddeningly confusing to use.
On the downside, this app can be confusing to use, and it requires you sign up for an account before you can save your final movies.
I found the next version, Word 6.0, to be a wheezing, bloated mess of recycled Windows code that was confusing to use and took no advantage of the built-in elegance of the Macintosh operating system.
Mr. Nureyev's sister, Roza Noureevandrancois, and her daughter, Gouzel, said in court papers that in 1992, a Chicago lawyer, Barry Weinstein, persuaded Mr. Nureyev, who was sick, weak and confused, to use all his United States assets to establish the foundation.
The model may seem a bit confusing to those used to the traditional approach to job boards, à la Monster.com or Indeed.com, but it's actually fairly simple.
The model may seem a bit confusing to those used to the traditional approach to job boards, à la Monster.com or Indeed.com, but it's actually fairly simple.
The concepts of germ cells and germinal cells are often confusing to pathologists, who use these terms somewhat differently than embryologists.
Previous work has shown that users find it confusing to correctly obtain and use public keys.
