I'm not sure antigen is much better than molecular, tbh -- from a travel logistics perspective. Free molecular tests aren't that hard to come by in the US -- we did Walgreen's last week and it was a breeze. The current molecular requirement also has the advantage of being valid 72 hours out. If you test positive, 72 hours is enough time to find backup accommodation (or cancel a hotel that you may have booked as a backup, which is what we did) and also enough time to cancel and/or rebook flights. Plus you have 72 hours to relax a little once you test negative! It seems possible (likely?) that a switch to antigen testing would also mean switching to a 24 hr or one calendar day timeline. That means worrying until the last minute that you might test positive, and really left scrambling if you do.
I'm not sure about travel to other countries, where molecular testing might be more difficult or expensive to find... and so antigen testing could be a real advantage... but this is a Disney forum, so....