Most people, particularly non-permanent resident expats, rent here. For non-PR stamp duty is very high. LTVs conpared to the UK are low, so you will have to put a lot of cash in to a purchase as a down-payment. Taking myself as an example, for us to afford to buy what we currently live in, we'd have to put a fairly large % of our net worth in to the property purchase, and that's not a gamble we're willing to take on the HK property market. And we only pay about 20-25% of our household income on rent, so it's not like we're living somewhere beyond our means.
We own properties in the UK that we rent out, and are happy to rent in HK. The one negative we don't like is not being able to make major changes to the property that you would if you owned it.
Just adding - I'm PR and have been here 14 years, so would get the lower stamp duty, but still choose to rent.