Do you think hiring managers gives importance to cover letters for resumes today?

YES Cover letter can be an effective marketing tool.
The covering letter is vital to your CV.
put your cover letter at the first page of the resume and not an addition 46% of employers preferred half a page and14% of employers preferred full page of the cover letter

Sure it serves as an introduction and short biography to me and I consider important

Yes ofcourse; as cover letters are snapshots of your resume, and also reflects your interest in the position applied for.

i think yes in most cases

Hi - Indeed a resume should be addressed with a cover letter, so that it is easy for the recruiter to recognise the applicant and through cover letter, writing skills can judged with, whether the applicant is aware about the latest trends in the market....

cover letter includes some of the experiences and achivements of a person and it reflect the person in overview so, its important. 

IN my Opignion as a manager too , the cover letter resume everything personal about the Manager , achivment , and the KNOW HOW , it is always important to know the person basic character before hiring .
to be able to put him in the right spot . 
 

YES 

Yes it does add an extra edge, If cover letters were not so important then its very existence would have lost.
A cover letter is a summary of a person's life and skills.
If you add a cover letter along with your resume then hiring managers will definitely go through it and surely it will have some effect on the outcome   نعم أنها لا تضيف ميزة اضافية، إذا كانت خطابات يست مهمة جدا ثم وجودها قد فقدت.
خطاب تغطية هو ملخص لمهارات حياتية ومهارات الشخص.
إذا قمت بإضافة رسالة تغطية مع سيرتك الذاتية ثم سوف تذهب بالتأكيد مديري التوظيف من خلال ذلك وبالتأكيد سيكون لها بعض التأثير على نتائج

I believe YES; as it shows the level of your professionalism and communication because it is a subjective letter which reflects one's vocabulary, grammer, writting skills, expression skills and a lot more...
It may be important for most of the employers specially for candidates who are required with strong communication and interpersonal skills.
  Also it contains your short introduction and brief career information as KEY POINTS which is important for employers.
 Most of the employers may have received hundreds of application for one post and he/she might not be able to read each and every CV in detail, instead KEY POINTS OF HIS/HER INTEREST ONLY.
 

yes ofcourse because it make easy to scrotanize the candidate skills by the emplyer