Actually, the study doesn't conclude bitcoin transactions will reduce 50%, it says the dollar amount of transactions will reduce up to 50%, which is a major difference.
Here's the study
http://www.juniperresearch.com/research/cryptocurrencyYou can find articles around the web with the conclusions.
Yup, that is way different.
If people were using bitcoins to gamble and bitcoin loses half its value, the dollar value of bitcoin transactions would reduce by half too.