If Dan Snow thinks he can do history by searching primary source material from the comfort and convenience of his office, I fear he is not doing very sound or thorough history. Yes, digitisation is making a lot of material available without the stress and strain of visiting actual archives, but as an archivist, and as a historian who has just returned from a trip involving crossing Canada from Toronto to Victoria to look at archival collections which it is unlikely will go online within the foreseeable future, I think I can state fairly categorically that any historian who thinks they won't ever need to go and get hands-on with the sources is limiting themself in ways that are very bad for the process of history.
I refer back to my post in late April flagging up the problems of what is given priority in digitisation programmes, how complete it is, how much necessary context is there.
I might also remark that in many instances I have encountered, repositories holding important collections of personal and institutional papers don't necessarily even have a decent online catalogue so that one can ascertain what they've actually got.
Plus, maybe the research Mr Snow conducts does take him to glamorous places, but many archives are to be found in locations which are not only not particularly places one would choose to visit for any other reason, but not even particularly easy to get to. (Though I will say, Victoria BC in June is lovely, even if most of my days were passed in a semi-basement furiously making my way through handwritten and occasionally typed correspondence.)
What has possibly transformed research in this digital age (from my experience on the basis of this recent research trip) is the ability to take digital photos of the documents for later perusal (I was fortunate to be working in special collections which permitted this). Having worked, in the past, in institutions where there was not even a routine procedure for obtaining photocopies and one was obliged to rely on the kindness and available time of the staff, or in other institutions where the charges were inordinately high presumably to discourage the ordering of large amounts, being able to take away images from collections which I had a very short time to ingest has been a major boon.