Good drainage is an essential part of any homes performance. Building garden beds against the home can cause issues that are detrimental to your home. The Building Code of Australia requires a fall of 50mm in the first away from the base of external walls
In this new home the builder has installed garden edging and stones that form a moat around the property filling with water when it rains. This will effect the homes future performance by causing excessive and increasing dampness to build up. In the long term it can lead to slab edge dampness, decaying base of wall framing, mould amd health issues. The water build up will also affect / negate the homes chemical termite barrier system. It's a good thing termites can't swim.
If your are looking at buying a home that has this garden system be sure to scrape some stones back to check as they can be dry on the top but still have water lying underneath.