1. All gatherers use the same stats, and all crafters use the samer stats. So you can use the same gear, it's just the tools that are different.
2. You still save it as a separate gearset for miner, botanist and fisher, because although they share the same gear, they do not share the same tool.

Saving multiple gearsets is also useful for glamour reasons - for example a christmas botanist and a halloween botanist.