Roger,
If you will occasionally encounter really dry conditions where you would need to use a polyester ( plastic ) ball as your main weapon, then YES, the investment is worth it because the xxxl is a much better strike ball than an ordinary whitedot.
If, however, you are only looking for a spare ball and NOTHING else, then NO, the expense isn't worth it.
I have them both and am speaking from experience. The xxxl strikes much better than the whitedot that I have, but is still very easy to go crosslane at the ten pin for me.
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What did you expect, something PROFOUND?
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