Yes, you can play at any of the online casinos without redeeming a bonus. In some cases, you'll need to inform the casino that you do not want the free bonus, because in most cases, it will automatically be added to your casino account. You can play at the casino in guest mode without receiving a free casino bonus, or you can register for a real money account and make a deposit to begin playing the casino games.
The advantage of playing at the casino without a casino bonus is that you can play for as little or as long as you'd like and then withdraw your winnings. There are no special conditions, restrictions, or wagering requirements that need to be met, because you are gambling with your own money. Playing without a free bonus gives you the freedom to start and stop whenever you choose, and you can play any of the games at any time and bet as little or as much as you'd like. When you win big, you don't have to worry about meeting any free bonus requirements.