One cannot separate the result a back four plus goalkeeper get from that of the midfield and forwards.
One can separate the result that Manchester United get from that achieved by Manchester United Ladies. That is what it means for a sport to be intrinsically a team event.
It is not unthinkable that some football tournament will be set up by way of an aggregated score between the men's and women's results: it would be nice to think that it already exists, and it probably does, at an amateur level where the social aspect is primary. But it would not mean that there is integrated reliance on the two matches such that one could not exist independently of the other.
The only interaction between the two halves of the national teams, apart from a little social bonding, was the triggering of a green light: that is not integrated reliance and interdependence.
(My nephew has a European gold medal for the team result in cross country: it could be said that I am arguing against my family's interests, but my issue is with the principle rather than his cabinet contents)
Let's turn it around: can anyone give a good reason why there should not be two entirely separate TTT events at major championships, just as there are entirely separate ITT and RR events?
My best argument would probably be that if an event is regularly contested at club level, it could also make sense to introduce it among the pros.
I don't have much knowledge about the history of mixed relay events across all sports, but it seems like the push from the IOC means it's not been something that has grown organically everywhere.
What I definitely do know, is that I have swum in a lot of mixed relays before they started to include them at major swimming championships from 2014 onwards. Of course in swimming and many other sports, there are also seperate relays for men and women, but I don't think that's likely to happen in cycling.
I find that standalone TTTs (sometimes ITTs, too) can be quite boring, because unlike in stage races, the time differences don't matter, so there might not always be that much excitement all the way through the races. In the mixed relay, there can possibly be more uncertainty. Today there definitely was.
After watching multiple ITTs over the past days, I also like that we have an event that is different from the other races, rather than just having two regular TTTs. However, I do agree with Toby and others, that there are multiple ways to improve on the current format, and that it doesn't have to be a TTT at all.