No, they most certainly don't make the application go any faster.
And we have seen countless cases on this forum where lawyers have made mistakes on apps, or don't notify the applicant/sponsor when they get communication from IRCC, causing massive delays and problems.
For most regular applications, it's far better to do without a lawyer. Lawyer should only be used if you have serious criminal or other complications, or you are incapable to fill out the forms yourself.