Note: Before I even begin, I want to stress that this is for the next election, not the current one.
I can understand why candidates may want to opt out of the moderator election chat room - for some people chat is just not their thing, and it is not an official moderator duty IIRC.
But I can't think of a good reason why answering the questionnaire is optional.
To me it seems quite disrespectful to not bother posting an answer to the much more important (IMHO) questionnaire, which should allow all candidates to answer - at considerable effort - the same questions about their platform and thoughts about moderation. This is very simply about transparency. This puts everyone on equal ground in terms of information voters have about them. Not answering the questionnaire may allow some candidates to rest on the laurels of their nomination blurb, or their existing popularity, to carry them through the election - without ever having to answer the hard questions about what they will do in certain very relevant moderator activities - ones that often come up as controversial.
For more direct evidence of the harm / ill-will that can be caused when a candidate can abstain from both the chat and the questionnaire if they so choose, here is a direct quote from a candidate in the current election:
I found it incredibly frustrating to have candidates leading the primary, blatantly ignoring the questionnaire - this increased when they were directly asked about it and they responded "what questionnaire?" How engaged will they be as mods when they don't even pay attention to the current process?
And another quote from a different candidate:
[Some] have just been riding the primary votes, no where to be seen in the election chat or make any attempt at answering the questionnaire. This is disturbing because all the other candidates have are putting forth an effort. The way I see it, the votes on the questionnaire should at least represent what's happening in the actual primary. This isn't happening.
Please consider making the questionnaire mandatory. One simple way to do this would be to make answering the questionnaire your official nomination.
This has multiple benefits; in addition to making sure that all voters are privy to all candidates' answers to the questions, it also avoids one seemingly unnecessary step in the process, prevents the current drive-by effect that nomination "votes" can have on an election before these questions are even answered, and potentially shortens up the election period.
That is just one possible implementation - and not one I would argue over. The important thing, in my mind, is getting all candidates on equal footing where they've all had to answer the hard questions in the questionnaire, instead of - or in addition to - whatever self-praising they want to emphasize in their own self-nomination.
It is obviously too late to change these rules for this election, but I think it is a change worthy of consideration for the next election.
From another site (Math) here are two meta questions that may not directly endorse my idea that the questionnaire should be mandatory, but certainly make it clear that the community finds it questionable when a candidate is relatively unknown, doesn't give the voting pool adequate time to review their qualifications, or doesn't participate in events like the town hall and other chats throughout the process:
By submitting at the last minute this user has avoided much of the individualized questioning the other nominees endured in the comments section of their nomination post.
Arguably you could say the same thing about delaying answering the questionnaire (or not answering it at all).