No, for Family based cases they use the I864 (which has a legally binding aspect on the sponsor). I134 is (without doubt) the correct form for DV cases.
A CO reviewing any immigration case (including DV) should consider whether the person will become a public charge or not. For DV applicants who are asked to show how they will support themselves, they can show any or a combination of savings (over $10k per adult), proof of assets that will be sold, a job offer in the US, or an I134 completed by a US legal resident. You may not be asked at all, but if asked for this proof and you cannot provide it, you may be denied or put on AP while you get the proof. So - you don't HAVE to provide it, but I personally wouldn't want to attend the interview without something...