I think Craig explained this in a video going around the park last week. I'm not exactly sure where in the 5 hour video he discusses it.
I just watched that one. Its the morning in Magic Kingdom one from last week.
Basically he explained theres 2 reasons behind it.
When they are in the parks, they have to pay to food and drinks out of pocket and then get reimbursed. Thats pretty standard for employee expenses.
As a result, they watch what they spend when they are filming in the parks, as like us all they have to watch their cash flow and sometimes it takes a while to get the reimbursement.
And the second and main reason, is like most staff, drinking alcohol while working and representing the company is not allowed. You have to remember, Craig, Ryno and Deni are employees and the whole purpose of the in park videos is basically promo for the
travel agency, to sell Disney holidays. Them filming in the park is basically like us hosting a company stand at a convention. You wouldn't be allowed to drink while talking to potential customers and representing the company at a convention, so the same employee rules apply to Craig, Ryno and Deni.
Also Craig said that before when they did do things like Drinks Around The World, they would stay on site, so that they didn't have to drive home. Again its all about representing the travel company and showing things which the travel agency customers want to see.
As fun as it is to see them in the parks and Craigs live streams are just so good, the ultimate reason he is there is to get customers for the travel agency. As a content creator, every time he goes to the park and live streams, he will have a plan and reason to be there and there will be a list of things he has planned that need to shown on camera.