Lol, well some games I use it and i fairly great. Maybe out of 10 games 2-3 of them i did bad in.

Ex. why i use it...chasing skele king and after his ult went off he ran and was almost dead..so i blinked on him and dead

Last night i blinked into their base/unloaded images and got sum kills.

in most team fights Tb can just cast slow use images and battle. But sometimes i like to blink behind them and attack. Bleh

You do know good players wouldnt run backwards if you stand behind them right? only noobs would do that cus they cant think when they are paniced/stressed

Maybe start playing some more serious games and you would understand why dagger is a 2k waste item on terror when there is so many other items needed for him.
I rather buy a vanguard for those 2k gold, and then go for the manta and some dps like butterfly or mkb.