Sure, you COULD just take your phone out and snap something just for the memory... But do you want something to glance at for 20 seconds every 6 months? Or do you want a professionally taken, trophy-like, beautiful memory?
One where both of you will look amazing and, more importantly, where the photography will BECOME an experience in itself, instead of subtracting from whichever activity you were involved in?
Remember, I'm here for you :)