The way I understand it, the stake-weighted poll has not been officially announced or endorsed by the ZF. However, it is available and offers all ZEC holders a permissionless option to express their preferences. But if the results have no impact on how the ZF or ECC will interpret the outcome of the sentiment collection process (because this form of polling was not officially announced, can be relatively easily gamed, etc.), ZEC holders may be better off simply creating a new user on the forum and participating in the forum poll. Their vote will have just as little impact but it might save someone the trouble of keeping track of the stake-weighted votes.
I personally like that the ZEC holder poll exists. It encourages those new to Zcash to learn about this particular way of interacting with the network and could be a stepping stone for developing a full-blown voting mechanism later down the road. Although someone with the appropriate expertise should make very explicit all the related security and privacy concerns.