[ slippage ]
I think that an important point with regard to this matter is that its significance depends entirely on the service in question. Services that only require a one-way transaction will not have this as even a potential problem.
But yes they will, the problem is 50% less than when exchanging back and forth, but it's still there.
Equally important is the fact that the issue is entirely addressable by the design of any given service (i.e. by a coin, not by the Blocknet), and these services have not been designed/optimised for the Blocknet.
For example, if a service requires that coins be returned to the client, then they don't actually have to be exchanged, and so an escrow service might work better.
This would eliminate slippage and thereby present a competitive advantage to any service that offers it.
And what would this do to anonymity set?
The point is that you're worried about something that is (a) readily surmountable and (b) hasn't arisen yet. You're pre-empting an issue and then worrying about it as if it's a real problem.
In my opinion, you should've worried about it beforehand (if you want to portray a professional and competent image to potential investors that is), and not after some people start realizing it's going to be a problem.
It isn't. In a free market of coin-based services, there'll be competition on a new level. Coins will have no problem inventing clever ways of rendering quality services and rising to the top of the pile.
The issue of slippage should be something that blocknet solves, so every coin can benefit from it. If it isn't, then a whole lot of perceived usefulness of blocknet just disappears.