I am not a fan of posts being paid out in SBD. As 1 SBD does not equal 1 US$, the value of your post is in neither SBD or US dollars but instead a strange weighted average of the two. For example, if both SBD and steem have a value of US$2. A post with a payout of $100 after curation would receive approximately 25 SP and 50 SBD. This gives us a payout roughly equal to 75 SBD or US$150 neither is $100.
If a person choose 100% SP payout, they would receive only 50 SP equal to roughly US$100. This creates the problem that nobody has any incentive to receive 100% payout in SP, thus making this feature redundant. If anything, the payout in purely SP should be slightly better as we should be encouraging people to invest in SP rather than take SBD payouts.
Receiving SBD payouts also adds another level of risk to those buying votes. If the price of Steem falls during the week, those that bought votes even with a positive ROI stand to lose. If the price of Steem rises during the week, the ROI will become positive. This could result in speculative use of bots rather than promotional use.
I am not opposed to the existence of SBD but I am opposed to payouts being made in SBD. If someone wants to hedge their risk, they should be able to buy a correctly pegged SBD to US$. I believe pegging to the dollar would be easier if we didn't have the added complication of payout fluctuations.