The phrase "a useful case" is correct and usable in written English.
It can be used when referring to a specific example or situation that serves a practical purpose or provides valuable insight.
Example: "In our discussion about software development, I presented a useful case that illustrated the importance of user feedback in the design process."
Alternatives: "a valuable example" or "a practical instance".
Whether the strategy was intentional or not, Gerry McCusker, who has written a book on public relations disasters, believes Kraft's experience with iSnack 2.0 will become a useful case study in using controversy to "cut through the clutter" of the marketing space.
The consistency of the threefold condition for the Cdx genes, maintained over hundreds of millions of years of evolution, attracts us to Cdx genes as a useful case for analysing gene retention.
Germany's own history of reunification is a useful case study.
A useful case study is to compare the ability of men and women in math.
After everything has wound down the two schools may have a useful case study to offer.
But before examining why, it's always useful to see what lessons can be learned from the past, and the Large Hadron Collider (LHC) provides a useful case study.
The case is of some interest in itself, but it is also, as the authors note at the end, a useful case-study in the kind of moves nominalists can make in eliminating unwanted ontology, and the costs of those moves.
With no evidence for a diagnostically useful case definition (used alone) and the potential unreliability of RIDTs [ 12, 36], new diagnostic strategies are urgently needed.
A particularly useful case of such a generalization is given by the use of complex numbers in Cartesian geometry.
The proposals for expanding broadband service offer a particularly useful case study because the potential benefits of wider network access are indisputable.
The region provides a particularly useful case study for several reasons.
