Googlebot is crawling my AMP pages more than they are crawling my desktop pages. I have the appropriate canonical from AMP to desktop and amphtml from desktop to AMP. The desktop version also has a self-referencing canonical. Only canonical pages are in the sitemap.
This is a concern because less than 10% of our traffic is from mobile devices (unique, I know), yet it's more than 50% of our crawl budget.
The one thing that we do, which I'm not sure if this is appropriate or not, is whenever a desktop page 1 links to an internal page 2, the AMP version of page 1 links to the AMP version of page 2. Therefore, there are internal links pointing to AMP pages, but only from other AMP pages.
The other thing I was wondering is whether anyone has heard of Google serving AMP pages to desktop users behind low bandwidth connections, where they could benefit from AMP. Supposedly AMP doesn't have to be for only mobile anymore, but Google hasn't really demonstrated this. We don't get a lot of mobile traffic, but we do get a lot of third-world / low-bandwidth traffic.