Yes I know that anyone can go on-line and view their data usage.
But you have to understand that the TB was the first phone with 4G which was completely new and Verizon wanted to see how much more 4G users would use data vs. 3G users. This "collected data" would help them customize their data packages by not making the data packages neither to large or too small. They want to make money on tiered pricing but they also wanted to be careful to not make the tiers too restricted and cause customer blowback (especially from 4G users whom will use larger chinks of data faster than 3G users).
By disabling the Data widget from the TB, users would not have instant feedback and therefore unintentionally throttle their own data usage by having their usage readily available. Yes, we all have unlimited data - so why would anyone "throttle" themselves? Because we are human and perhaps (either because of ignorance or sub-consciously) use less data. You have to remember that we all here on these forums would probably not care how much data we are using but 90% of TB owners are not phone fans and are not on these forums. Therefore would most likely think they "are using too much" and limit themselves.
To be clear, they have tons of data on how much data 3G users use on a monthly basis, but they never had any hard evidence on how much 4G data customers use on a monthly basis so they needed to collect that data. Who else better to collect that data from than brand new TB Owners?
And to clarify the Online Data use vs. the App Widget - Of course anyone can go online and check data usage, but having it instantly available on your phone would likely skew the true results they were looking for. Also, users are less likely to power on their PC, log into the site, and pull up their data usage. But when it is right on their phone a click away, they are more likely to do it more often.
As a software tester myself and in the IT Field for over 18 years, I guess I can see that this was done intentionally more than someone that is not in the field.
I'm not here to go back and forth since this fact really has no bearing on my life in one way or another. This is my opinion and i'm sticking to it, but of course you are free to disagree!
Cheers