1) Is for GR keys.
2) Is for upgrading low-level gems.
3) Is for XP. Run higher GRs, which you can still clear fast enough consistently.
Yes, this can very much be done solo, and no it doesn't require "14 hours a day". You won't get there with a few hours a week, I'll admit that, but let's please not pretend people don't get to paragon 1000 because they're not playing in a group. What's more important than to group up is to know your class, know the game mechanics, and play efficiently. Then paragon 1000 solo is perfectly doable.
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I use my wheel to move its a lot easier once you are use to it you. no longer have accidental clicks on mobs or pylons. For me makes using my left click for spells a lot easier then having to stop or hold shift down to force stop my moving so i could fire.