I'm not sure. I think that without it, I would rediscover the lost art of summoning the scroll function using the two buttons on the mouse. I am not sure how, but I mastered this back in the Windows 98 days, where some combination of the two keys would have the same effect as clicking the scroll wheel has.
When it comes to games I would manage, there is often another just as easy way of zooming in and out, and I usually change weapons with the number keys anyway, since I always forget which way to scroll to get the right weapon.