Should we keep cats indoors?

I personally think that we should keep our cats inside at night time because 1 so they don't get killed or run over at night time, 2 so that some of our cats don't kill our native animals, because some of our animals go out far into tree areas, and they can eat our native birds or geckos, but I don't think they should be kicked out of our country, because some of these uninvited animals are also killing our native birds and so on, they are also passing around diseases and passing it to our animals.

FUN FACTS:
1. The cats around Wellington caught around 43% of native animals, the other 57% were animals brought to New Zealand.
2. This is a Photo of what cats eat and how much they can eat in 3 months.
3. They average cat kills 13.4 prey items per year.
4. 1/3 of the cats didn't bring anything home.
5. 20% of the rest were frequent hunters. 

HERE IS A LINK TO A SLIDESHOW ABOUT !CATS!