I like the fact that Lisk focusses on usability (javascript dapps) wich can trigger mass addoption.
But since bitcoin is having serious scaling problems already, and ethereum will too, how is Lisk going to address this?
Good question, this topic interests me too.
This is one of the major advantages of Lisk over the other networks. Running the dapps on sidechains instead of the main chain makes it much more scalable. As many servers to run dapps as are needed can be added to the network.
Bitcoin and Ethereum are trying to address scalability with what amount to patches on top of the core technology, like Lightening Network for Bitcoin and State Channels for Ethereum.
With Lisk, scalability is built into the core design from the ground up.