The phrase "a useful face" is correct and usable in written English.
It can be used in contexts where you are describing someone's facial expression or appearance as being helpful or beneficial in a particular situation.
Example: "Her smile was a useful face in the tense meeting, helping to ease the atmosphere."
Alternatives: "a helpful expression" or "a beneficial visage."
I am a useful face for the politics people to have a go at.
Peake will no doubt be a useful face for UK space science, but decisions on whether or not to change the longstanding policy on human spaceflight will be up to politicians.
She rejected claims A4e had found jobs lasting at least six months for fewer than 4% of people referred under the work programme, adding she had been a "useful face for the politics people to have a go at".
Emma Harrison, who quit as chairman of A4e in February amid fraud investigations into the firm, said she had been a "useful face for the politics people to have a go at".
As he learned more about Hitler through his reading, he began to regard him as a useful face of the party, and he later admired and even worshipped him.
Many useful face detection systems use various basic theories [3 6].
She's less interested in the sad little home she's wrecking by sleeping with Sean or in the pain she's causing his "zombie" wife, Aileen, "whose little fat sits in sad, middle-aged pouches about her boy's body" and who wears "very middle-aged lipstick, pinkish and pearlized, on her unprepossessing, useful face".
Frustrated by the return of the rain, Ireland can at least take some comfort from a battling effort against a useful Windies side who now face England, New Zealand and Sri Lanka in the next stage of the competition. .
Both the reduction and emergence of new unexpected diagnoses are important parts of the diagnostic process and US showed to be a useful means to face this step.
In either case, to obtain a useful model, we face different challenges: (i) defining the system's mass flow structure (stoichiometry), (ii), deciding the appropriate mathematical representation (kinetics), (iii) estimating the parameters that make the model response consistent with experimental data (parameter estimation), and (iv) inferring the system's regulatory structure.
A useful mantra in facing the feelings and thoughts is to recall that you must be responsible for your own happiness and they don't have to control your life.
