Welcome to AT!
It's perfectly OK if all you do is collect, compare and enjoy the artwork. You don't have to do readings at all. But, maybe, like Grizabella suggested, you could try doing a few more 'serious' and deeper readings, just to see if you're perhaps missing something.
Originally, I was drawn to Tarot because of the possibility to do readings and get answers to the questions I had trouble finding. At that time I saw no use in owning more than a couple of decks. However, it grew on me over time.
And it's awful to think now how much I'd miss if I'd stuck to my original idea - to stop buying when the number of my decks hit 5.
Readings actually needn't be about 'global' questions, but it helps if the questions are really something you'd like to know about, and it worries you. I once did a reading about my home makeover. It was one of the most illuminating readings I've ever had, and it was incredibly interesting to me because it had practical use there and then. In another reading, I asked Tarot how to deal with a 'difficult' relative, and it gave me a very simple tip that helped me to become closer to that person. Perhaps, you could try to do a few readings that would yield practical results, and that might show you a totally new facet of Tarot readings.