There can be several channels, and accounts in the same messenger can be connected to each of them. It’s convenient for targeting customers. For example:
A retail chain can assign the phone number X to the store at one address and the phone number Y can be assigned to the store at the second address;
Channels can be used to separate advertising sources: for example, in advertising of one kind you use channel X, in advertising of another kind - channel Y;
Companies working with large brands can sort customers by channel depending on the subject: channel X will serve customers who want to buy one brand of car, channel Y will be responsible for cars of another manufacturer.