Can 100% security be guaranteed?
Every opportunity comes with a cost. One thing that comes to my mind is that if someone had developed one App with a cost, why he will give his customers free of cost. You are using the App or services which means that you are the first customer. You are the data and asset of the App developing company. They may not do any direct business with you but your information/data could make the App development company the next millionaire or billionaire. For instance, see the business model of Facebook, they acquired WhatsApp and now WhatsApp got very popular with the power of instant messaging and have entered into the payment business after they saw good customer base. They may even move into banking if the payment business becomes a success. After you are used to the communication method, it becomes difficult to leave a technology behind. If WhatsApp wants to charge a certain price (may be a small amount) for using its App, I am sure at least there will be 70% conversion rate. It