I am assuming it sets my character back a ways. Is there a benefit to it and how is it utilized.

It just resets your char to lvl 1, that's it. You keep all your proficiency and items. It will just unequip the items you were wearing. Can be useful if the monsters get to tough, or if you want to go back to lvl 1 to join a group or pick a different class

The benefit is that you can adjust your character build based upon your lessons learned on your initial climb

You lose no gear, you lose no proficiencies.

Thanks for the response.

The benefit depends on the person using "reroll".

I found it beneficial for Prof gains and collecting self found gear years back. Now it can be used in the same manner if starting out and no fg and for hard Events when you have nothing good to use... so check the Events that happen every 3 days, look out for "+X% Monster Difficulty", in some cases it can also be hard for a lot of people even with gear.