Yeah that's a good question. I am personally not a big proponent of those tags because "great first issues" are simple by definition, but if the maintainers did not fix them it means that they are low priority. Do you really need to fix a simple bug that hasn't been fixed in 2 years and that doesn't affect you?
What I have seen is people trying to fix a "great first issue" for the sake of contributing something, and not actually needing it or caring a lot about it. Many times the fix was obviously not sufficient, and I ended up spending more time reviewing and supporting the new contributor than it would have taken me to write the fix myself. That would be fine if those people became regular contributors afterwards, but they didn't, so I basically lost my time.
Really, the best contributions I have received were from people who actually needed them. And those people did not need an existing issue (with or without the "great first issue" tag) because they were the ones affected by it. For simple bugs they would just open a PR directly, for others they would open an issue offering to contribute and asking for help. I was always happy to help them of course: my point was that they did not need my guidance to find what to contribute.
What I have seen is people trying to fix a "great first issue" for the sake of contributing something, and not actually needing it or caring a lot about it. Many times the fix was obviously not sufficient, and I ended up spending more time reviewing and supporting the new contributor than it would have taken me to write the fix myself. That would be fine if those people became regular contributors afterwards, but they didn't, so I basically lost my time.
Really, the best contributions I have received were from people who actually needed them. And those people did not need an existing issue (with or without the "great first issue" tag) because they were the ones affected by it. For simple bugs they would just open a PR directly, for others they would open an issue offering to contribute and asking for help. I was always happy to help them of course: my point was that they did not need my guidance to find what to contribute.