Powered redstone only connects to pistons

The new feature added on 0.15.3 allows redstone to connect to redstone inputs without using repeaters. I am sure that there is a tweet from a developer that said that they might connect the redstone signal to other inputs too. In 0.15.3, only pistons can be connected to redstone, but other inputs, namely, dispensers, droppers, and redstone lamps, cannot connect to the redstone when it is powered.

EDITED:
See attached file below