There are a lot of casinos online, we even see new casinos coming to the markets each week here on the forum. But if we divide the normal/land casinos with online casinos, i think those places have a bigger wager in total than the online casinos. Just think about Las Vegas, can you imagine how much is the total wager just in that city? We know is the biggest gambling city in the world, but the point is, the users wager there more than the total wager from online casinos in the same period of time.
I agree with you land base casinos have higher volumes in both revenue and traffic and as you mentioned Las Vegas and a few others like the land casinos in my location, it is suited in one of the highest reputed hotels and have Large staff based so it shows higher demands and revenue overall, but when you talk about popularity and ease of accessibility, online casinos is topping that ranks, there is no way gambling industry will have been complete without online casinos, it came along with the wave of cryptocurrency which aimed at privacy and easy accessibility at the same time.