Choose the way you are comfortable sending the messages in your chats. In other words, with Channel, you will have an option to send the message by hitting the "Enter" key or the "Command/Ctrl+Enter" keys, making it convenient to converse.
With Enter preference, you will be given single-line spaces in the chat footer expanding when moved to a multi-line message by long message or by the Shift key. While with Command/Ctrl+Enter preference, you will have space for multiple lines in the chat footer. Here Enter key will allow you to move to the next line.
In situations when a user wants to send a message with 3-4 sentences to an individual or group, the best way will be to send it together in a single message if they come under a similar topic. In case of sending 3-4 different messages, the recipient will be notified for every single message received, which might disturb and distract him/her from their in-hand work. On the other hand, sending a single message makes it easier for the recipient to read and reply accordingly.
It is also useful in cases where a first-time conversation is taking place. A sender sending a “Hi” and waiting for the reply then accordingly taking the conversation further makes it difficult to converse as well as makes it time-consuming. So with the help of these preference-changing options, one can smoothly shift from one to another as per the convenience.