I use TWINT and e-banking daily and I consider it very safe!! However, you need to pay attention to your behavior… smart people are always ready to trick you.
Past experience (to learn🙂): I purchased an item on an online marketplace and sent the money with Twint. The seller never sent me the item. Made a police report –> They identified the culprit (because the telephone number and therefore the twint number was registered to a person) but he reported to the police “I lost the SIM” and therefore they cannot blame him because it could be that the SIM has been used by someone else…..
Moral: The applications work and are safe but always be careful there are always those who find a way to circumvent the rules!!!