Where I'm at in general on application telemetry — at least for Elixir Phoenix apps
1. Sentry. Very nice, straightforward Elixir integration. Gives me information about most 500 errors — e.g. problems the app knows it's having.
2. At some point I start wanting performance information and especially wanting to see what's occasionally weirdly slow. At that point: traces into Honeycomb.
3. Eventually I add metrics to the Honeycomb integration.