Actually I'm quite surprised that the PLA seems determined to get WZ10 in service, given that there are quite some armored fighting vehicles, SSPs, tanks waiting, and they are much cheaper.
Dear Sir:
The attack helicopter provides the army commander with long-range, mobile, accurate and flexible fire support with a rapid response time. It can, on short notice fly-out and perform strikes on the enemy while your artillery and armor are still on the approach march.
Although strike and dedicated ground-attack aircraft also perform this function, the helicopter's ability to hover and hug the terrain closely allows for much intimate coordination and close support.
In combination with other types of helicopters - surveillance and transport, it allows an entirely new type of operation - vertical assault; which the Americans pioneered in Vietnam.
As the army's ground formations all over the world are now in the process of downsizing, helicopters give you a tremendous boost in capability with less manpower, albeit at a high cost.
Best Regards,
Dusky Lim