One big difference between physical board games and digital ones is how they deal with complexity. If players forget about rules in a physical board game, then they're playing a different game. So you have to work hard to make each rule count, to make it both intuitive and easy to use. If there is a conflict, inconsistency, or just confusion the rule system, then that can bring the game to a screeching halt as the players argue about which way it works.
Digital board games have a final arbiter for rules: the game itself. Videogames do not forget rules. You're not allowed to make illegal moves. And so forth. This allows you to have lots more rules in a videogame than you could in a physical one. If there is a conflict, then you either code a solution or the game works itself out (or crashes).
But complexity goes farther than that.
In a physical board game, players are often required to keep track of certain things. Some board games give units stats, for example. But players have to keep track of such stats as they change throughout the game. That's hard; it requires upkeep and effort.
For a videogame, it's trivial. Oh sure, you need to present this information to the player in a digestible form. But the player's focus is not on remembering to track the HP of all of their units; they don't have to do math and subtract numbers during combat. They just have to know what the current value is.
By some measurements, Civilization and its ilk are "digital board games". You could make a physical board game equivalent. But it would be pretty much unplayable due to the sheer amount of stuff you have to keep track of. Harvesting your food and leveling up cities. Counting up how much production each city made and finishing any construction projects that it completed. And so forth.
What a computer does instantly when you press "End Turn" would require minutes or hours of mindless grunt-work by each player.
So there are entire design spaces that physical board games would never enter which digital ones can. While needless complexity is generally bad design for any kind of game, videogames can handle greater levels of mechanical and rules complexity without breaking down than physical board games.