How many reasons should you put forward in a presentation?
If you have to give all sorts of reasons, you have just told your audience in essence that “This thing is going to be complicated.”
Rather than doing that, build one big, powerful reason. One good reason is good enough. Your task is to share it. If you spend time adding a lot more reasons, you are communicating the idea that this is going to complicated.
Of course, difficult decisions are not black and white. They are nuanced so you need to present several benefits to overcome several negative effects. But in those cases, start by highlighting the pain points we are going to avoid by making this good choice.