Very much this. I know a lot of people who regularly get vaccinated, who are skeptical of this one. For many factors, not the least of which is it's not just a vaccine for a totally novel virus, but a completely brand new style of vaccine which has never been used before.
While I can see my son and husband getting vaccinated right away, my daughter and I won't, because we both have existing health issues that put us at higher risk of complications from the vaccine. But, once we have some time to see how it's going, how people are reacting, especially people with pre-existing conditions, and it's deemed safe, then by all means, sign us up!
I know there has been a lot of chatter in the mainstream world about vaccine certificates being required for international travel - like there already is for several places. And I absolutely expect that to be the case with Covid. But I don't see it being a requirement domestically, and definitely not at Disney.