The main reason is that SWAT teams are more heavily armored, not just armed. It is for the safety of the officers and the residents nearby. Especially if someone is suicidal they may be willing to shoot at officers to get a return response.
It is a cryin' shame that life had become so bad that this individual felt he could not stand to live any longer. If there is anything good that came out of this it is that those police officers who responded can go to bed tonight knowing they did not kill another human being today, because the other human being killed himself rather than committing suicide by cop.