What's the difference between public and private links in "Megas"?

Public link view is @ChannelName or https://t.me/ChannelName.

When forward by such link, the channel opens and “JOIN CHANNEL” button appeared. 

Private link view is https://t.me/joinchat/AABDAEdXoVf8Vwit8W7TzQ.

When you forward by such link user can't see what's inside till he subscribe on the channel. User will get pop up notification that contents a question "Do you wan to join the channel "ChannelName"? So user can't see the channel content if he's not a subscriber.