Additionally, cross-platform communication between different devices or operating systems can lead to message conversion. For instance, if you're using an iPhone to send a message to an Android user, the message may be converted to a text message format to ensure compatibility between the two devices.
Another potential reason is network compatibility: In some cases, the recipient's device might not support the same messaging platform you're using, prompting the app to convert the message to a text message to ensure it can be received.