Hello,
The out-of-the-box Email Send and Newsletter channels that come in a new Marketo instance actually do have the same program statuses (Member and Influenced, with Influenced as the success status) and are both associated with the email program type, so there isn't a difference in that sense.
The main purpose/benefit of having separate channels would be for reporting purposes. If you want to compare the performance of general email blasts with a primary call to action (i.e. Email Send) to newsletters with a number of sections/links (i.e. Newsletters), you could want to keep them as separate channels. Perhaps they're run by different teams, have separate budgets or have different goals or expectations. You can filter a Program Performance report by channel.
But if you don't distinguish between the two for marketing performance reporting, then no worries - you don't have to use both channels and can hide/delete one for clarity.
Here's a community blog on Channel Best Practices for additional tips.
Cheers,
Beth Massura
2022 Adobe Marketo Engage Champion