Hi Navrark,
The ID checks are in place to protect both PokerStrategy (from fraudulent multiple applications) and yourself (so that we know who you are and would know if anyone else pretended to be you).
They are straight forward and all data/pictures provided are treated in the strictest of confidence and never provided to anyone outside of PokerStrategy's customer support team.
It's a one-off process and once completed, would not be requested again. For info, all poker platforms also request similar before you withdrawal, again to protect you and ensure that you receive the money and not someone pretending to be you.
You do have an alternative to providing ID, you can deposit your own funds into one of the first deposit bonuses provided by PokerStrategy. This way, you would not be entitled to the free $50, but would still earn PokerStrategy points and enjoy all of the other benefits membership here provides.
Hope this clarifies your options better, best regards for whichever route you decide to take.
Bart