the first Chorm pack you get, is set up to give you a character. Many people, will restart new accounts over and over, until they get a good first character then move forward from there.
it helps in arena, because again, it will start you over, and in a new shard. arena shards are built 1-20k people. after they hit 20k, a new arena shard starts, and people will fill that one. So what this allows you to do, is
a. get a good character ( that will be good end game )
b. refocus your arena squad, to be something very competive and retain the top 1 - 10 slots.
3 mil, is not really a lot, because once you hit 50, you will start leveling mods, and those, cost a lot. the high the rating, the more it costs to upgrade. there are many guides here, that will explain to you how to farm out mods and get the best for your credits ( teachs you which ones to level, and which ones to just sell to not waist credits )