[jabroni_salad]

Yes, your domain can end up on a blacklist such as SORBS or Spamhaus and then you will have deliverability issues across the board. I have also heard from many companies and individuals with personal domains that have difficulty with Gmail and the verizon/aol/yahoo postmaster. They will just bounce you out of the blue.

DMARC and friends only help with authenticity. There's plenty of fraudsters sending authentic spam out there. The cost of a new domain is like $6, and there's plenty of people inputting their credentials on fake webmail signin pages for spammers that have trouble maintaining a credit card.

[stavros]

This is all true, but I don't understand why email providers will bounce personal domains. If you run DMARC and your domain is years old, what's the issue? I imagine that reduces the risk of spam by a lot.