As I was told recently this is one of the worst tasks to be given and not realising this, I had volunteered a bit too willingly. It requires a huge amount of cross referencing and checking and triple checking and sampling lots of different products some of which all have long lead-in times and represent wasted time and money if not used.
This is no different to any other aspect of working on site and preparing the fine detail so the Contractor can order products in time and budget for them so there is no huge surprise for the Client. I have been in this profession for long enough to know that the success of a building project relies heavily on a combination of people skills and the whole is greater than the sum of the parts.
I can see why working on ironmongery schedules in isolation from the joiners (who are an integral part of the team) would be incredibly difficult and might not achieve the desired outcome which is on time and within budget.