@Narf Feels like you are the ignorant one. You have severely underestimated the world setting in the story, the skills you are given determines your value especially as an adventurer. It's not like its a situation where Note is just an average person compared to Erin who is a prodigy but more like a person at the absolute bottom compared to a prodigy. The manga didn't really state the difference between World Map, Area Map and Mapping, the translation wasn't that accurate either. World Map maps the whole world and stores it as knowledge, taking up 3 skill slots, Mapping maps 1km radius around any previously travelled point and stores it as knowledge, taking up 3 slots as well. Other than the fact that Mapping can be used in dungeon which only
few parties like the Arrivers exclusively target, World Map is clearly superior. Area Map on the other hand, maps a certain range around the current position and provides the info to the user however it only costs 2 slots, allowing for another skill to be obtained.
The problem lies here in that value of the skills are determined by others. Like Jin said, along with how rare Mapping users are, most of them realize the futility and choose to become something other than an adventurer, Note probably would have given up if not for his childhood friend stringing him along. This is why few people know the dungeon mapping feature of the skill, even Arrivers couldn't confirm it, it was just a theory. People ask why didn't Note learn Arts earlier, simply because he couldn't afford to. Arts require practice and teaching which no other party before Arrivers had the leeway to do so with Note. Adventuring is a risky job, with how useless Mapping is, the parties he joined are pretty weak. Arrivers could afford to teach him because they saw value in investing in him and also simply because they are strong enough to do so. Jin didn't start from zero like Note despite what the manga showed, his crafting skill only took 2 slot and he had a very top-tier combat skill called Absolute Shadow that boosts his speed tremendously. The two people are not comparable at all, Jin could practice with what he had and used creative ways to fight, Note have no such option. Erin on the other hand is absolutely a powerhouse with her 2 magic skill that synergizes perfectly, it's delusional to think that she needs to put in the same amount of effort as Note to even stay in a decent party. TLDR: Talent in this world determines your fate.