Controlled demolition is precise and was the last chance they had for this to work

You cannot ask rescuers to dig in patently volatile conditions if there is a way to make it safer.
The original area, although much more dusty, s still intact for investigation & search, but now much more stable. Any uncontrolled collapse would have made everything worse.

Supposedly they made the implosion fall away from the original debris. They said with the storm coming in it was very likely to fall and if it fell that way it would definitely fall on the original debris.