Graphite can be converted to diamond and this conversion is favourable under high pressure and high temperature.

Is there a reason for this from the point of view of "Le Chatelier's Principle"?

I tried searching the web and found explanations based on thermodynamics. Being a high school student, I don't know much about thermodynamics yet.

Anyway, below is my hypothesis:

Graphite has low density compared to diamond. Hence, it occupies a larger volume.

When pressure is applied the system tries to minimise its effect (in accordance with Le Chatelier's Principle) by decreasing in volume converting graphite into diamond in the process.

Is my hypothesis correct? What is the role of high temperature in all this? Have I missed any important details?