Lots of professionals, including me, use InDesign for newsletters.
It's not an intuitive program, however, being targeted to the professional designer who is expected to have an understanding of page layout and print design already, and there will be a learning curve.
I strongly suggest that if you choose to use InDesign, that you spend a little time learning the basics from a good source, rather than flailing around with (as Peter said) a non-intuitive but extremely powerful tool.
(1) If you prefer books, this is the best: Visual QuickStart Guide by Sandee Cohen:
(2) If you prefer videos, David Blatner's beginning series on Lynda.com:
You can get a week for free from Lynda.com.
(3) Or, if you prefer a more personal touch, look for a class being taught in your area.
Lynda.com have an excellent online tutorial that's a step-by-step guide to producing a newsletter using InDesign, Illustrator, and Photoshop: Watch the Online Video Course Designing a Newsletter
and these three programs are included in the Adobe Creative Suite and you can pay for them monthly.
And of course you can return here to ask questions about specific issues that may (will!) arise.
One more thing: many people new to this look for the "one app" that is used by pros. In fact, pros use InDesign for page layout, Illustrator for vector illustration and Photoshop for photos and scans. Often all of them are used in a day.
It is most certainly NOT simpler than a web based template, but it is the tool used by professionals to make actual magazines and so forth. To do a good job they may have years if training. Still, you might consider a simpler tool aimed lower.