How do you determine what is relevant? Not all people are solely money-driven. For example, for me, there are other important aspects in a photovoltaic system:
[*]optical design [*]as high self-sufficiency as possible - because even if I pay to a green provider - here the electricity comes from lignite power plants. What I do not draw from the grid is really clean.
Therefore, for me, a battery storage is not only a mathematical exercise but also a means to achieve the goal of covering as much of my own electricity demand as possible.
I deliberately did not write anything about the storage issue; the pros and cons have already been discussed here several times, and no common denominator has been reached.
I think that for many system operators, the ecological and economic aspects are relevant when considering installing a photovoltaic system. Fortunately, both requirements are not mutually exclusive in a photovoltaic system; on the contrary.
If the three points mentioned above are read from top to bottom, one recognizes the positive interaction between ecology and economy.
To achieve a high self-consumption rate, you have to build a system as small as possible. The larger the system, the less of the generated electricity you will be able to use yourself. But that is not bad at all because others can use your green electricity, and that is good for the environment.
So one does not want to consume as much as possible oneself but rather draw as little electricity as possible from the grid. That is a fundamental difference because to achieve low grid consumption, you need a system as large as possible that still produces a relatively large amount of electricity even in lean times.