You have to ask yourself why there is more crime in poor areas. The answer is that we don't go looking for or don't care about the crime that happens in other areas as much, and that the socio-economic conditions lead to more crime. You can't fix these issues by sending police there to act like an occupying army. You can only fix the root cause.
As a personal anecdote, having grown up in such places, people have so many bad experiences with police that they genuinely don't want to call them when their presence might maybe help. So is sending police patrols to maximize the number of arrests and create ever more negative experiences the solution? No. You have to fix the root cause.
Removing criminal elements from communities creates safer communities, which is a prerequisite for people thriving.