Remember it wasn't just the William and Kate 'approach'.
The whole expectation of a country was on it. Especially for Prince George. This was the first royal birth since Eugenie. We had a month of the #greatkatewait. Literally hundreds of media organisations camped out in front of the Lindo Wing.
As with everything to do with Harry and Meghan, they have much more latitude.
I guess Louise and James don't count as royal births ?
With that being said, the presentation/photo-call helps build a connection with those small numbers who do care and also helps socialize the family into the broader cultural story. Now, there are lots of other ways to do that now, in the social media age, to be sure. And even in the time since little George was born, social media has exploded/advanced in ways that the younger royals could do better to take advantage of.
I personally want a Sussex photo-call because it was a fun experience with the Cambridge babies in terms of fandom conversation. So very selfish on my part
But I also think it goes a long way helping manage media issues (paps trying to get photos, etc) and building media relationships. Now, the UK tabs have been terrible, but at the end of the day, the BRF, no matter the individual royal, needs them for their work to truly land. So Harry and Meghan would be wise to have some mass/prestige media aspect to the birth for that alone.
Plus, despite their great skill at keeping out of the spotlight when not working, it wouldnt be shocking if news leaked of the birth happening. Without proper media briefing, protocols and plans, that could turn into a mess very quickly.
All in all, we will see what path they take. Not long now!