Just to be clear, jury instructions are read TO the jury by the judge before the jurors are sent to deliberate.
Whether the jurors get to "read" the instructions depends on the jurisdiction, I think. When I was on a jury, we had to request that specific instructions be reread to us by the judge, just as we had to request that testimony be reread to us. We weren't given hard copies of either.
I asked and was told that a lot of court rules stem from the days when many jurors weren't literate. It was thought that jurors who could read would have an advantage if printed material were given to the jurors (because those who could read could "prove" their point with the printed pages, whether it was written or not).
For the same reason, up through 1985, New York State didn't even allow jurors to take notes. (This may have changed.)