Why? The main reason why I like imageboards is the anonimity and being able to just shit out your opinion based on the logic of your arguments, or if available evidence as well. This upboats system feels to me like it's going to just make people base their arguments and opinions on the hivemind, instead of what they actually feel about the topic at hand. You may say the following;

>the voting system is fine because we don't know who voted for what, and the votes are anonymous
You may not know who voted or not, but a VISIBLE identity around these upboats will form. People will start changing their posting habits to get these upboats or risk being sagebombed or have their thread ignored. Having a visible marker, or gauge of the "community's stance" on a topic just seems antithetical to the concept of being able to post anonymously to me. Those are just my 2cents.