The main reason for role addresses is people change jobs.
It's much easier to change a mail server alias so reception@ or sales@ points to the new staff member or a team's mailing list than to contact every client that has ever received that address and request they change their address books.
Addition for clarity:
From a business perspective, clients want make sure they can always get in touch with someone to help them, yet have access to specific staff members for client/account management or higher level support/sales when appropriate.
To achieve this goal, my recommendation is to use both both techniques; staff should have personalised/named accounts, and be members of a alias or mailing/distribution list for their department, role or branch -- whatever delineation makes sense.
What address is given out or used then becomes a business decision of expected follow up / personal contact / historical knowledge required, staff turnover and how "general" client requests are (example, password resets can be performed by any helpdesk staff member)
For front line customer-facing roles, departments with high turnover or where requests can be completed by any staff member, clients can be provided the alias (support@, sales@, reception@) for that department, guaranteeing someone from that department will receive their mail and be able to look after them. When a staff member leaves or changes role, it then becomes a matter of changing the alias or mailing list subscription.
For roles where a high level of personal contact, historical knowledge, or where the work can only be performed by specific staff members, contact can be made using the named account. I'd recommend the client should be provided with an alias address as well so they are not left out in the cold when a staff member leaves the company or is on leave.