Do we need batteries to stored solar PV system energy?

I am trying to build a PV system including an inverter/charge controller which combines charging the batteries from available source (AC mains if not the PV when possible) and delivering AC output to the selected load in case of mains cut out.
Energy is a more general and comprehensive parameter related to both power and the time this power is in use. Either power or its usage time can affect the final consumed energy and this is what a PV system shall be designed for, with uncertain and variable power over a variable time. For guaranteed instant enough power in an off-grid system you shall have batteries and in on-grid system there is no guarantee as it depends on irradiation level. When you have plenty of sunshine with almost no variation, and people fed-up with batteries problems they don't want to hear about the Energy philosophy.

Sunshine is powerful but intermittent and weather dependent while we used to get power from a reliable and stable source like a power cable fed by a distribution company. don't forget that most of solar power being generated now around the world is fed to an already established base load stable system using fossil fuel and without them a stable power network cannot be established with just renewable energies.

Solar production is not constant throughout the day even it is a very bright sunny day. This happens because solar depends on insolation(sun light), temperature, losses like mismatch, wiring, dust etc., If you run your loads with instantaneous production from solar panel, the life of motor/ lamps/ other loads fluctuates as per production and reduces the life of loads. So you need to have at least requirement nominal battery/grid connection to support constant input to your day loads.