Its not the size that counts… hehe. It really isn’t of any use that small but the idea of having that with a large touchscreen would be extremely beneficial. Its similar to the whole IPv6 thing, you have a huge amount of IP’s available which will never be completely used anytime soon. However, in 20 years we might be at the same place we are with IPv4. Its all about thinking about the future. Since everything seems to be going towards touchscreen you’ll need to have a multi-touch feature. Think of Star Trek TNG and later… they use Multi-touch touchscreens (if they actually existed back then).
In short, there really isn’t a benefit to it right now, but in the future when touchscreens come down in price and they start getting bigger this technology will really kick in.