I would compare it to locking my vehicle. Stealing is against the law and even so, someone may be able to get in there by various means to take things. Maybe even the car itself. But that still doesn't deter me from locking it whenever I exit. Of course it's not a bullet proof method to keep my things completely safe but I'm not about to stop locking my car.
I just want something simple to package everything into a file rather than leaving all my sprites out in the open.
Your analogy isn't really equivalent; yes you lock your car because it makes it harder to break into, but:
1) This increased difficulty for the thief increases the chance of their detection.
2) Which encourages the thief to go elsewhere.
Obfuscating your resources (or code) doesn't increase the chance of detection (it remains zero), nor does it encourage the thief to go elsewhere (if they need what you have, you are the only source).
Moreover there exist tools, that operate at the binary level, able to identify & rip image, sound, and video assets both from disk & from the in-memory representation.
Obfuscating your resources might deter the casual browser; but the casual browser isn't the one who is going to use your assets in a damaging way. (They may in fact be using them in a constructive way, building a wiki or the like)
Thus you're at best
wasting your time, and at worst
impeding fans of your game.