The value of a project is the worth, to your organization, of the consequences that would result from doing that project.
Project consequences must be valued in a common unit of measurement, otherwise they can't be combined to obtain a total measure of project value. Since financial gain is an expected consequence for many projects, dollars is the obvious unit for measuring all project benefits (including non-financial project benefits).
Value must be expressed in dollars, otherwise, it will not be possible to determine whether project benefits justify project costs. If you can compute the dollar-value of the alternative project portfolios conducted by each of your organizational units, you have the ability to optimize the allocation of capital resources across your organizational units.
Many commercial tools cannot accommodate valid models for computing the dollar value of projects. Instead, they require users to rely on scoring or point systems that assign a numerical "figure of merit" for comparing projects and/or express the value of alternative project portfolios as a "percent of total value."