You can really trust new cryptocurrency trading app especially if they have good feedback where many people already use that app. I have seen a lot of cryptocurrency trading app but not all them capable to help all newbie to trade well and they do not have some tutorial that will guide all newbie. Many people especially professional trader still prefer to use the tradition and major exchange like Binance, Poloniex and Bittrex. However, Binance already have an app where you can trade you cryptocurrencies. Just like what I said earlier some of new crypto trading app do not have some beginner mode where will assist the trader so I recommend to try the new upcoming exchange which is Bitrus where will have beginner mode will totally guide all newbie trader and I also waiting to release this exchange because I am also beginner in the field of trading.