Plus we need the steem and sbd burn system like that or whatever so that at least it will help with the price of steem.

Exactly!

My question is that can we send sbd and steem now to @null for a hope of curation benefits? Thanks.

Yes. See the examples section in the post. If you send at least 1 STEEM, your post will be reviewed. If you send at least 1 SBD, you'll be reviewed and also be seen in the promoted section. But remember to use the correct format (@author/permlink) if you want to be seen on promoted.