They base all their assumptions on a wobble. (By the way, how can they know that this planet is tidally locked? And that alone makes this a very un-earth like planet)
Would you spend trillions of dollars, hundreds of years, and at least hundreds of lives on an expedition to this planet? Just to see what is there?
Other things that strike me as funny:
The planet is estimated to be 3-4 times as large as Earth. (Earth like?)
The article makes it sound like life is even more possible to develop there, than here, because it is tidally locked. If that is so, and it being only 20 LY distant, then we should be able to pick up some kind of EM transmissions from them (since they have probably had more time to 'evolve' than us because of their more perfect conditions).