Dial Caliper, calibration question

Hello,

I am considering purchasing a Mitutoyo Dial Caliper 0-150mm/6 inch.

I was thinking “How am I going to calibrate it?” And I was considering buying some gauge blocks. But then I realized that with the dial caliper, the dial will be on zero when the jaws are completely closed if it’s calibrated properly.

So, would I really need to calibrate it if the dial is showing zero when the jaws are closed?

Thanks in advance!