A quick warning to all gambling beginners, the most attractive ways that scam gambling websites get to you is bonuses and undeniable offers, I can see some new online casinos coming up with attracting bonuses to make you deposit some money and gamble, while they still have no reputation build yet but the offers are too good to the eye that you want to try it out, be cautious.
Without putting out bonuses and offers how do you expect these new casinos to attract new users from the forum to expand their user based if not through those exotic bonuses. Reputation is not built in a short time, it takes years and these new casinos deserves to be given the benefits of doubt as did to those old casinos in the forum when they first arrived.
Like @Oshosondy said, the only cautiousness to apply is not by refusing to make use of these casino's but in making use of them for our gambling we should deposit money we can afford to lose in case of a scam happening.
New casinos also comes with baggages likes
1. Experiencing several issues like game loading or lagging.
2. Experiencing errors when trying to deposit or make withdrawal.
3. Lower withdrawal limits.
4. Limited currencies accepted, most prefer Fiat still.
5. Lack of games collection due to limited software providers.
6. Lack of online reviews about them, some even have their ways with fake reviews.
For a new casino these experiences can't be falling short of them certain collection would be lacking so it's isn't a sharp end for conclusion , any old gambler that have tested varieties of online casinos shouldn't see these "garbages" as something to not worry about for a scam, with time they will improve in those features and errors.
Reviews are a good way to know about the repute of a casino but new casinos may not have those much reviews you might be looking for as they are just new into the market. Though some reviews are paid reviews so I don't 100% place my points on reviews.