Do you think bonds are good investments? Their returns are so low though.?

Low returns = low risk. It depends on your risk appetite. If you can't take risks, then the returns are good enough for you.

Yes, every asset class has some place in someone's portfolio. If yo're young , you may not want so much bonds in yor portfolio because you could be looking for capital appreciation.

But when your strategy becomes more conservative and you want steady income instead, bonds would fit right into what you're looking for, as they pay guaranteed coupons and provide capital protection upon maturity.