Your Blogger blog even supports your use of a custom feed. If you setup the Post Feed Redirect option, all links in the blog that would reference the native blog post feed are replaced by the custom feed. Your blog readers, when they click on a link that says
Click here to subscribe to my feed!automatically subscribe to the custom feed. This is good for your readers, and for you.
Unfortunately, use of the feed redirect option isn't a good idea for everybody, immediately. If you're using a Google Sitemap, to make it easier for the search engines to index your blog, and bring you more readers, you'll need to use the native blog feed.
With the blog redirecting all blog post feed references, to a custom feed, the sitemap will be broken. The Google Sitemap requires a feed that has the same URL as the blog. A custom feed has the URL of the custom feed service. This breaks the sitemap, unless you modify the feed URL.
Having modified my feed URL, I can create a Google sitemap that the spider can work from.