Our product doesn't use bitcoin on-chain to settle every transaction (that'd be impossible at scale). We use a payment channel that resolves all transactions into a single output once the channel is closed. We can scale with no issue currently, everything works, so far. As we continue to implement SegWit and other optimizations, the system will be even more robust and secure. Bitcoin is not a hinderance at all whatsoever. We chose to go with the most secure, most immutable blockchain by building with Bitcoin; and to take advantage of the massive network effect and huge merchant adoption to empower users to SPEND the money they make on things they want, very easily.
This is covered in our latest blog post more concisely by our CEO, Ryan here: http://engineering.yours.network.