There is no magic wand club or golden bullet ball, but if you want to compete, you'd be doing yourself a service to use the better gear...balls included. Going to the new ball might be only .4 strokes/rd, but for many, that's good enough. All those little fractions of strokes add up and do help.
Do you need the best gear to multiplay and have fun in this game? no, but at least you have the option. My complaints with this game are numerous, but based on it's "body of work" and the fun I've extracted from it over the past few years it has been worth it...for the most part, and I like having options in the pro shop. I only wish prices would be more realistic for a game.
The thing that grates on me most is the apparent lack of respect WGT displays for many of it's patrons (Elite collection anyone? or how about the terrible marketing, or terrible community involvement/support to name a few), the constant "tweaking" of physics and VEM, and a few specific things that are ridiculously unrealistic (i.e. sand play, the apparent vacuum over the edges of the fairway that stop pushing your ball, early break in putts breaking more than late break etc,).
But, at the risk of redundancy, if you want to compete at higher levels (or be competitive rather), you need the top gear.