I do believe that USSD is very important. The fact that I did not realize that it was not available until I arrived at Hong Kong back in late December. My whole vacation that was about a month and half was such an inconvenience because I couldn't do certain things on my prepaid sim card. This includes check my balance, recharging my balance, using cheaper idd service, making international call while I was roaming, and sending international sms. Heck, whenever I needed to actually add some money to my sim card, I had to literally find a retail store for them to do it for me because I did not had an extra phone on me. The worst part was when I was in Taiwan, I was there during that huge earth quake that they had. I was unable to call my family to tell them I was safe because I couldn't use USSD. That really scared my family for that week I was there.

Having internet on the N900 all the time is not a given. Also, not all sim card's balance can be checked on the net. Since a city like Hong Kong relies heavily on USSD, I don't conclude with you on the fact that USSD is a niche feature from old technology.

P.S. I totally did not realize that the N900 was missing USSD features until halfway through my vacation. I keep thinking that I was not following the instruction on the manual properly that came with my prepaid sim card......