Going anywhere on the globe in half an hour, instead of up to 29 hours, is of course very appealing. How can ballistic technology be used for the purpose? Will cost be acceptable for average passengers?
Welcome to Aviation Stack Exchange, and interesting question. I assume you know something about the ballistic process for vehicles such as ICBM's and so I'll start my explanation from there.
Firstly, ballistic anythings don't account for the acceleration's effect on humans. Only machinery and weaponry has been transported in this manner, and I don't see ballistic missile technology becoming well adapted for this purpose anytime soon. Just look up the acceleration values for a Trident III for example, and you'll quickly see that you and I would definitely not want to get on one of those.
Secondly, ballistic technology is single-use. Missiles obviously have a terminal point, where it blow up as it were, but an alternative like rockets and space shuttles present a more suitable option for us humans. At a much shallower trajectory than ballistic missiles pose, space shuttles provide a fast, but highly inefficient method of travel that we rarely use anymore, and most definitely not for mass commercial purposes.
Long story short, ballistic missiles specifically would not be suitable at all for humans, if we want to board and disembark alive. Some new options, such as the Sabre rocket/aircraft are promising new technologies, but for our safety and efficiency, traditional aircraft are still the prime choice.