The IETF contains some really questionable propositions lately, not sure what to make of this, but it doesn't seem to solve a problem. What does this provide i

The IETF contains some really questionable propositions lately, not sure what to make of this, but it doesn't seem to solve a problem. What does this provide in contrast to DKIM? Perhaps there are logistical problems with DKIM, but I wouldn't know. I wonder why it isn't more widely spread in the first place. The receiver can determine the requirement, which is the best solution imho. For Google it seems to be more of a marketing issue than security. Furthermore provider could track domain requests. That isn't just suspicious, this is almost malicious. There is a reason mail clients don't display pictures outright. I hope my mail client will never support this.