Honestly, I was surprised that they had a bomb available. The next day, I heard someone on Fox complaining that police are under funded and had their tactical gear taken away.
If you have a bomb at the ready, I fail to believe that you are under funded.
"Bomb" is a relative term... from what I gather, this was a piece of C-4 attached to the robot arm with a crude remote detonator. The object was to take the shooter out. For starters, the shooter was armed with an SKS which fires 7.62 x 39mm FMJ (Full Metal Jacket) rounds with 123 grain bullets (standard); as compared to the AR-15 which fires .223/5.56mm NATO rounds firing a 55 grain bullet (also standard).
Considering that the AR-15 is the usual semi-auto rifle of choice for law enforcement, this one shooter had the police outgunned, and was wearing body armor to boot. They tried to talk him down for almost 2 hours before the robot was used to terminate the engagement. This guy was operating in a military combat assault mode against civilian police. The use of explosives as a last resort was a good call, with no real alternative that did not involve killing more police officers.
Dallas is lucky he only went after the police. Had he decided to hit civilians as well there is no telling how many dead there would have been.