How important are certificates like the ones Microsoft gives, for an employer?

Several Factors are there :

-Filtering the certified out of the non certified reduces the candidates for interview (TIme is money for them)

-It may be company policy to handpick certified candidates ( In case of Quality Investigation)

-90% of companies opt this way hence you will have more opportunities 

It willbe a great Identifiaction for the employee who can show his Elligiblity for the Entrance of the company..