It's clear that they will make a centralized off-chain thing. It's the only way to make it
free and instant.
About
secure, well.. we all know how secure are the online services handling Bitcoin. They're all "state of the art" until proven otherwise.

What do you think about that?
It's centralized, so you'll have to give really good reasons to people to transfer money into your system.
Would you use it? If you don't, can you explain why?
Most probably not. Why? Lack of trust, and I don't really need to send transactions to other persons. You'll need a huge user base in order to work.
What features would encourage you to use this service?
You need to be backed by a known name, an institution that'll reimburse the users in case of something wrong.
And you need to add a huge list of merchants and service providers (including exchanges) into your user base.
Then it may work, despite the centralization...