3. It will let you interact with other people which is good for socializing.
I think this is only applied for physical gambling, not for online gambling.
Anyway, I don't think interaction during playing gambling with others will be very useful for socializing purposes. You won't talk freely or speaking much while playing, which probably impairs concentration.
5. It can be a source of income.
NO, mate. I don't think you can rely on gambling to get income. Instead, you mostly lose money on gambling as the chance to win is quite small. It is more reasonable if you expect for the entertainment of fun by playing gambling. However, it depends on the gambler's own perception, whether he views gambling is a money source or a fun place.