You
Is a sitemap worth it for twenty pages?
ChatGPT
It helps discovery on a new domain with no inbound links, which is exactly the situation a fresh project is in. Once pages are linked from anywhere indexed, the sitemap stops mattering much, but it costs one file to keep.
You
Any downside worth knowing before I commit?
ChatGPT
It commits you to a format that is tedious to migrate away from later. The first weeks also look worse than doing nothing, which is when most people abandon it.