The usual conspiracy theory is that Signal is funded by the CIA and therefore a honey pot.

what menssaging app should i use for secure communications? i need an app that balances simplicity and security.

Signal. I can do almost everything that i.e. WhatsApp or Telegram offer, is as easy to use as those and the client is verifiably encrypted and secure.

how to explain it to my friends who use signal because i recomended?

Explain what exactly? Why they should use it?

• It offers the same functionality as other messengers while being verifiably secure and encrypted.
• Signal collects only three datapoints of users
  1. Date of registration
  2. Date of last connection to the server
  3. Your encrypted backups if you enable cloud backups
• Compare that to messengers such as WhatsApp and Telegram where it is not clear which information they collect, whether they store it in an encrypted format or not or who they share it with.
  • In the case of WhatsApp it is at least the US government as required by the Cloud Act.
  • In case of Telegram the data is unencrypted by default and cooperation with various governments has been reported.

what this means for other apps in general?

Please clarify the question.