I don't blame them for not wanting to put out too much personal info in their content, especially with Sam his channel's always been about the parks and attractions and not at all about his personal life.
I think he's getting more comfortable being involved in them as they get further into each vlog filming, but if every single daily vlog started like "Hi everybody, I'm here with my fiance!" that feels like a bit overkill and forced. Especially considering how many other vlogging couples make that their whole identity - Jackie can be too over-the-top for me sometimes, if they had an in-your-face couple dynamic like OA, BLAB, WDWCouple she'd be much more unwatchable for me.