I would say that it very much depends on how much of a pinch it is on your budget.
If you are better off than most, then it might be worth doing once.
If you are pinching pennies to take this trip and watching every dime? Well, you certainly can do this on your own for a fraction of the cost and some creativity.
We did it for DD10's birthday and she really truly enjoyed the whole thing. DD8 joined her and they are set for the rest of their lives. We won't be doing that again. May do the pipsqueek in a few years.
We also did CRT that day.
We made it a big deal. But that was our last time at Disney for a while as well as we moved to Virginia.
Your child won't be emotionally scarred for not doing it. The only issue we saw that day from admirers is that DD10 had a special Birthday sash that they provided her and a few moms asked us where we got it and once we told them, they were disappointed to not be able to get one. But you could easily make your own version of a sash at home as well.
They do let you bring your own costume though--so if you did just the base package, it wouldn't be too bad. We paid for the experience...not just the look.
HTH!
Fairy Godmother also showed up while we were there.