I liked to tell people, your expected loss per hour was lower on roulette, because of the time it took between spins, vs (for example) $5 a hand 21, or craps. Even though those two have better player odds. I had a hands per hour table from the industry, which I have lost long ago.

https://www.roulettelife.com/index.php?topic=358.0

Some assorted reasonable answers.

I have played the electronic at some WI Tribal casinos, the spins are much faster, maybe once a minute. There's no waiting for bets, the machine has no chips. If you don't get the bet in on time, tough luck, the game locks out betting.