If (!) it is really the case that such measures are necessary to justify photovoltaics, then I would refrain from photovoltaics! For all I care, install a conduit in your house, so that in 10 years, when there might possibly be practical energy storage systems, you can retrofit the photovoltaics.
You even quoted the sentence that does not make the statement universally valid.
But for most single-family houses it applies:
Expensive: connection of different heat generators although one is sufficient.
Inefficient: total oversizing of the heat generators due to combination of all generators that can rarely or never work simultaneously.
Prone to errors: 3 different heat generators that all have to be combined together instead of one heat generator that is perfectly tuned to the heating. Mm, true. That rather argues for the combination.
The forum as well as the internet is full of further reasons.
Morning
In biomass heating systems, for example, a connection with buffers and other heat sources is not only sensible but often necessary.