The twitter overlay was just an added point to illustrate that the politician was really at these places. Otherwise one could start with "yeah, well the meta data could come from anybody. Who's to say that all this data really belonged to him?"
I hope I don't have to point out how the metadata alone is useful in tracking suspected terrorists. You have GPS, SMS, timestaped phonecalls etc. Anybody who gets to request this metadata from a cell phone provider for Person X can track that person across the country. You might as well wear a Lo-Jack that is directly connected to the authorities. Same result, it would just be a little easier for them to access that information. Now, they still have to request and actually receive the meta data from a customer of the cell service. Unless of course NSA and company already have complete system access and the request to receive the meta data is just a formality.
My understanding of the argument is that the mass collection of metadata, from every phone number in America, has not provided any security benefit. For those who feel that sacrificing liberty for security is acceptable, sacrificing liberty to gain no security is probably not.
Collecting all of the data from all of the citizens in the US, or any country for that matter, is in fact counterproductive, as it creates a great deal of background noise, drowning out the useful data on the subject of interest (also it is illegal to conduct surveillance of US citizens without a warrant... Not to mention all US citizens without a warrant.) I don't think many people would agree that tracking everyone in the US is useful for tracking 'terrorists'. Unless you are talking about collecting data on every citizen to stop future crime that has not happened yet. If that is the plan, that sort of surveillance might be useful, if say ordinary citizen 9834202 decided to commit a crime at an undetermined future date.