Short synopsis is:
1. You cannot have a long lease of a house ( but you can of apartments, duplexes etc).
2. There is an anomaly in the law in that certain covenants and obligations in freehold transfers are likely to be unenforceable.
3. The preference therefore where you have an estate ( so that you can enforce the covenants and therefore ensure a peaceable and well kept estate) is to sell by way of long lease, thereby ensuring the enforceability.
4. Where you have houses, what can happen is that you would own the freehold of the house, but only have a leasehold interest in the common areas, services, roadways and footpaths etc, thereby ensuring the enforceability of the covenants in relation to the common areas( called a lease of easements).
However I have seen title in estates where the ownership is freehold and therefore the enforceability of certain covenants is questionable.