Sorry! <blushes.>
I need lots more than 1 Tarot deck just as I need more than 1 person in my life - they give me totally different things:
Intellectual. There are so many systems, themes, interpretations, ways of looking at life & its problems; even when using similar symbolic / allegorical / mythic structures.
Emotional. The colours, styles & general 'feel' of every deck enhance my mood or change it subtly, providing visual / intuitive expression of whatever is preoccupying me at the time, and often clarifying myself to myself.
I also find my many different decks immensley challenging or comforting in their various ways, according to my changing needs.
Philosophical. Isn't it endlessly fascinating to see how many apparently endless ways there can be to use & express the 78 windows of Life, The Universe & Everything?! Insights abound, & I learn something new every time I contemplate my cards.
Spiritual growth. Meditation & personal development of open-mindedness & open-heartedness outshine even traditional 'reading' to answer specific questions for me. I learn to see my world in ever-expanding ways.
Aesthetic. Obviously, the wonderful diversity of artwork, design, colour, shape, overall 'feel', sheer beauty & sometimes amazing expertise of the artists fill me with admiration & uplift my spirits.
There! Enough, enough, I hear people cry. I'm sure many of us love our many Tarot decks in all their rich diversity for just those reasons & more.