It is completely useless for me. It's also completely useless for deaf people, or for people whose phone system doesn't interface well with yours, or for many other classes.
That's not necessarily a bad thing; it's an essential characteristic of the service. Just be aware that you're excluding a lot of people.
Your particular application takes advantage of the synchronicity issue. Other than that, the only issue that applies to everyone is the cost.
That's not necessarily a bad thing; it's an essential characteristic of the service. Just be aware that you're excluding a lot of people.
Your particular application takes advantage of the synchronicity issue. Other than that, the only issue that applies to everyone is the cost.