I generally avoid alts for myself, and one of the benefits I see is that I feel the weight of what I'm about to post.
Maybe I would sometimes writer funnier, snarkier things on Twitter that would get more likes, but because my name is attached I'm forced to reconsider. Is this actually mean? Do I really believe this? Does this joke go to far?
Strange to say perhaps, but I think not having alts makes me a better person, in the sense of being better at being the type of person I want to be, because I can't hide behind anonymity.
I originally wrote this a year ago, but just now found it in my drafts. Not sure why I didn't post it then.
One flavor of response I got with my post on deanonymizing accounts was roughly:
Why not just go ahead and post the list of alts? It's not like people sneakily using multiple accounts is something we should be encouraging!
I do agree there are ways people abuse alts / burners / throwaways. You shouldn't be making new accounts to get around bans, or to give the illusion that an idea has more independent support than it really has ("sockpuppeting"). But there are also some good reasons to use them:
Separating aspects of your life. Perhaps you post your political views under one account and your work views under another. This could be because an aspect of your life is stigmatized, you have a career where you need to interact with people with a wide range of political views, or you just would prefer to keep clear boundaries.
Lowering how much weight people put on your views. Some people consistently post insightful and well-considered comments or have a position in their community where they are highly respected. Having a separate account to post idle thoughts and participate like a regular human lets them post things others won't take overly seriously.
Protecting yourself from retaliation. Perhaps you are one of many who know about some harm, but due to threats none of you would be willing to post under your real names. Some kind of anonymous whistleblowing could be very positive.
What's acceptable can also vary by community. For example, on Reddit making a new account just so the username can contribute to a joke you're setting up is part of the culture, but on a more serious forum that would be seen as an abuse of the account system.
Overall, I find the benefits of keeping everything under one identity are really high, and I suspect many people underestimate the value they'd get from that approach. But if others decide in their situation the tradeoffs point the other way, and aren't abusing alts to mislead people, then go for it.
This is part of why I posted on deanonymization: if it's important to you that readers not link your alt back to your main identity then you need to take active steps beyond just using a different username.