I think it's because they might make these special presentations feel like a Disney+ movie now. I think a special presentation is more than enough to get some more punisher content. Plus, we already got a punisher show, which is now Canon to the MCU along with all the other defender shows. The reason why daredevil is getting his show was because it's the most popular show from that saga. But regardless, I'm excited to see the punisher back.

I think the bigger question is why not let him have his own R-rated MCU movie. I would like to see more special presentations, but remember the GotG Holiday special, they are not just for introducing new characters. We know that Marvel Studios is scaling back the numbers of shows and films per year. So a special presentation is better than nothing. I still would rather see him have his own film, along with Daredevil as well. 

You try to make a Punisher show on top of everything else. It's hard! The amount of stuff they're pumping out already is ironically sabotaging them by oversaturating the market, one more show just might cripple them