Decreasing interest rate effect on economy Central banks decrease sometimes the interest rate by saying this has positive effect on the economy and the development of countries.

One of the reasons is that it can be easier to do investments (business, government, etc.). Are there other reasons? And does somebody have deeper insights about doing this and the benefit of it?

(Of course there are also disadvantages and risk of doing this (but I am not interested in that for now))
There are many channels of monetary policy transmission. You could look that up more if you're interested. I'll point out some of them here.


Interest rate channel. This is pretty much what you mentioned in the question. The opportunity costs of borrowing money becomes cheaper, so private demand expands.
Asset price channel. With the lower rate, people find it more attractive to invest in other assets (as opposed to keeping money in the bank). The increased asset demand leads to an increase in equilibrium price, which increase wealth for those who are holding those assets, and more consumption due to the wealth effect.
Exchange rate channel. The lower interest rate would cause funds to flow out of the country (people searching for higher yield in other countries) causing the currency to depreciate. The depreciated currency helps exporters to be able to compete and export more.