Why is kelvin scale regarded better than Celsius scale?

I don't think its better, it simply depends in what context you want to use it.

eg in household, celcius is better since 0 is where water freezes so easier to talk to your friends...

But for science kelvin can be better since 0 is the absolute 0 point (you can't go lower) and the range you use in science is larger, think of the temperature of the sun or melting metal, etc