Personally, I think it depends on the game.
Some, like Phantom Leader, I much prefer the tactile interaction with the game over playing it on an iPad. I don't have the control nor the 'at a glance' information on the iPad like I do when the board game is spread out before me.
Now, something like Blood Bowl, I totally see what Cyrano is saying. I played the game way back in the late 80s, as well as Dungeonbowl, but soon fell out of playing it. Kept an eye on the game over the years until the most recent 5th edition, and have been sorely tempted to buy it - but the base set is about $100, and team sets range from $30-$50 each, which is insane. Given how fun the BB2 game is on the PC, with its animation, voice acting, sound effects, and the like, it's light years better. I'm sure there's old school peeps out there that say the board game is far superior, so it's just a matter of opinion.
There's also the time you have to invest in painting your minis, which I don't have the patience for, nor the knowledge.