As someone who interviews for professionals/graduates, I pay zero attention to the grade of a degree as it is (in my experience) not a good indicator of how good you will be at the job.
A degree tells me you have an understanding of the degree subject matter, can read and interpret data and pass exams. It doesn't tell me that when I bring you in and start you working that you will be able to undertake the tasks I set you even with mentoring. I've had graduates with a 3rd who could run rings around another member of staff with a 1st, I've also had engineers with no degree but with work experience that have far exceeded their counterparts with a university education.
Exactly this.
I have an honours degree, and a master's degree (at distinction) but I assure you that a degree proves than an individual can work hard. It does not (across the board) prove knowledge and, with some candidates, it doesn't prove ability either.
The entire education system is rife with this same issue - grades/scores/ranks are meaningless when you are assessing the ability to regurgitate a statistic, formula or definition that has been drilled into you 'in the way that the examiner is requiring'.
A true measure of intellect, ability and achievement in my humble opinion, is how a candidate has dealt with certain events in their lives - completing a degree when caring for a sick family member, starting at the bottom dealing with all the crap that colleagues and bosses through at you, yet you persevere and deliver, and get promoted for it. And so forth.
Sadly though, at every stage in life whether vocationally, academically or personally, you will encounter setbacks and people who want to hold you down - either out of fear or jealousy, and the issue comes when these people hold a position of power over you (thereby preventing promotion, or a good glowing reference).
Other measures of intellect and ability are through psychometric testing and other problem-solving tasks - the sort employed by big blue-chip companies, certain government offices/agencies etc.