Why is the address for an account regenerated whenever coins are recieved.

[Jaxkr]

I was looking at this page, and I saw something that I don't understand.

getaccountaddress will return the same address until coins are received on that address; once coins have been received, it will generate and return a new address.

Why does this happen? What if I want my an account to have a persistent address, which always goes to that account?
Please explain what I don't understand here.

[Jaxkr]

OK. I understand now. It's so it can check that the account has been funded more easily.
Still, is is possible to have a persistent address?

[limitless]

This is in the wallet.. or ?

[Jaxkr]

This is in the wallet.. or ?

This is a Bitcoind command.