No encryption, no peace of mind

People often bring this up as an issue with Telegram, however if you want large casual groupchats with easy syncing and access to bots this is how it has to be. The moment 3rd party bots enter the equation end to end encryption has a hole in it. Large numbers of people also cause the encryption to be moot if one of the people you invite in are saving their logs and such.

Also while the default chats arent end to end encrypted, they are still encrypted. This isnt as as strong but it means your ISP isnt casually able to sniff around whatever youre sending.