There are no keys to the @null address (as far as I know). In practice that anything that goes in there cannot get out, ever.

So therefore any Token send there is getting destroyed. It is like burning money. Meaning a Token that gets 'burned' becomes more scarse.

If a Token can be inflated, Ducat does not but Hive does, it can mean that in the future new Tokens still can be issued, yet staying at the same amount in total.

This way burning Tokens (sending them to the Null) can create a circulating economy, instead of an inflating one.

Another aspect of the Null address is that the 'burning' of Tokens can be proven by just checking its wallet.

It is in essence the same as sending Tokens to someone's address that lost the keys. But with the Null address this is done by design.

Hope I was able to clearify it for you.