What Moon does in a chart
Moon is the part of the chart that answers one question:What do I need in order to feel safe? It describes emotional needs — not events, and not outcomes.
What Capricorn does to it
Capricorn is a earth sign, so it moves on evidence and consistency. It is also cardinal, which means it starts things. Put those together with Moon and you get needs control — structured, patient, ambitious, applied specifically to emotional needs.
Capricorn is ruled by Saturn, so this placement tends to be coloured by structure and commitment as well.
The useful version
Placements are not verdicts. This one describes a default setting, not a limit — the things listed above are what you do when you are not thinking about it, which is exactly why noticing them is worth something.