Surely if you can pick from all the women in Spain, you should be able to find 11 competent ones?
In politics the problem tends to be that there’s not just one quota, albeit that the women-quota may be be the only one that’s openly communicated. First you can only pick from people who are already at a certain career level in politics. After all you want someone who actually has experience for the job and a network to be able to get things done. Plus these people will already have been vetted properly. Less of a risk of an embarrassing story coming out with someone who’s been in the spotlight for years.
Then come quotas for different (left-right) sections of the party, then quotas for different regions and so on. Each of these reduces the number of available people exponentially. It wouldn’t be surprised if the number of candidates ends up being in the double digits. Even if we ignore qualifications completely.
So yeah, the quotas aren’t helpful to get qualified people. But it’s obviously idiotic to blame gender-quotas alone.