Probably there is some misunderstanding about what they were refering to by security/stability here. It's not about any service that we provide. I think they are just referring to the possibility that there is some bug in the SPS code. It's been tested by us (and reviewed by Steemit Inc as well) and I have no expectation that there will be any security bug of significance. But if such a bug was found, it would just be a matter of fixing it. I think all they mean is that they don't want to have it handle too much funds until it's proven safe by usage in the real world.