CCD is a technology, a strategy or approach to a specific problem if you wish.
diodes are semiconductors, with a positive and negatively doped region (optionally an intrinsic region in between).
A CCD also relies on a diode semiconductor bandgap to liberate charge carriers when a photon exceeding the bandgap energy strikes.
What is your actual question?
Is it "Why don't we use SPAD's in our cell phones and web cams?" ? Thats like "I don't know what it is, but I want it too".
You can't use these in brightly lit scenes, the lighting needs to dim enough in order to register electrical pulses due to individual photons. Instead of a single electron-hole pair, SPAD's are reverse biased beyond "breakdown voltage" such that the released charge carrier will in turn release others (the "A"valanche in SPAD). The breakdown voltage and reverse bias (together with a dark current) means the sensor will heat up. So it would need significant cooling and energy consumption (higher currents per photon at higher breakdown voltage) at normal daytime light intensities. The sheer rate of photons would not allow individual photon pulses to be discriminated as their pulses would overlap... The reason it's not in your phone is because it would be expensive, power hungry (decreasing battery life) and require cooling.