NO! You must go to your nearest PADI store, empty your wallet, and become certified as "Night Diver". Otherwise, you will DIE!!!
I'm sure this was said partly tongue in cheek but strangely you're the first person on this thread to suggest that.
There have been, however other posts suggesting how to approach it and some reminders of the potential risks and pitfalls.
One of the reasons I asked if the OP had been diving with his/her friend before and the reason I asked how much experience the friend had was to get an idea of some of the risk points I see (inexperience, unfamiliarity, possibly incomplete or untested skill sets)....
Like you, I have limited use for "cards". But unlike you I recognize that taking a course has another function, which is to gain that first introduction to a new aspect of diving under controlled conditions.
This is not to say that the OP cannot offer "controlled conditions". I don't know him/her and for all I know they are the best night-diver on the planet. What I *do* know, however, is that instructors who have been working for very long develop an incredibly sensitive "radar" for problems and in most cases an incredibly acute ability to "avoid" problems.
So yeah, I understand what you're saying, which is that a "specialty" for the sake of taking a specialty can easily be a waste of time/money but on the other hand, I would like to suggest that not all specialties are a rip-off.
R..