If you tell me that a company has sold $3m in shoes every year for the last 10 years, I might believe that they are going to sell $3m next year as well. However, there are tons of other variables that may be important, such as other companies entering the market, issues with morale inside of the company, or the overall economy.
If, in comparison, someone tells me that there are projections that the company will sell $3m next year, if I believe the people who are making the projects are at all competent I am going to assume that they not only had access to historical data, but that they put the time to look into a bunch of other factors.
In essence, unless I believe that the projects are put together by people whose knowledge of the shoe industry is less than mine (which is unlikely: I know nothing about shoes) it is actually the case that the projection is less of a gamble (aka, has less variance) than trusting my interpretation of the "measured" historical information.
If, in comparison, someone tells me that there are projections that the company will sell $3m next year, if I believe the people who are making the projects are at all competent I am going to assume that they not only had access to historical data, but that they put the time to look into a bunch of other factors.
In essence, unless I believe that the projects are put together by people whose knowledge of the shoe industry is less than mine (which is unlikely: I know nothing about shoes) it is actually the case that the projection is less of a gamble (aka, has less variance) than trusting my interpretation of the "measured" historical information.