For me this:
says only that the chord symbol C7(b5) defines 4 notes, wich is nothing unusual. All 4 tone chords define 4 tones. All 6 tone chords (like C7(#11) define 6 tones.
Wich scale to play when the chord is played depends strongly on the tonal context. But in many cases the WT/HT scale can be played when a C7(b5) is sounding.
Assume the sheet shows a G7 chord and the tune is written completley in c-major. The first scale choice will be c-mixolydian, because that is the 5th mode of the g-major scale and the G7 is the 5th chord of the g major scale.
Now assume the tune is written completley in c-minor. Then the first choice to play over G7 would be the phrygian-dominant scale, wich is the 5th mode of the harmonic minor scale .
Chords don't imply scales. The choice of the appropriate scale to play depends on the chord sounding and the actual tonal context ( and: taste, not to forget).