What is wrong with following installation steps of latest nodejs on Ubuntu 14.04?

Why can't I simply install latest nodejs. I have executed curl -sL https://deb.nodesource.com/setup_7.x | sudo -E bash - after which i executed the following

ubuntu@ip-172-31-2-33:/$ sudo apt-get install -y nodejs
Reading package lists... Done
Building dependency tree       
Reading state information... Done
nodejs is already the newest version.
0 upgraded, 0 newly installed, 0 to remove and 188 not upgraded.

ubuntu@ip-172-31-2-33:/$ whereis node
node:

ubuntu@ip-172-31-2-33:/$ which node
ubuntu@ip-172-31-2-33:/$ node -v
The program 'node' can be found in the following packages:
 * node
 * nodejs-legacy

OS is Ubuntu 14.04

via ishandutta2007