>Almost all PV is connected to the grid, there's no point in having a battery

It really depends on your usage patterns. For me it could be a great investment to get batteries if I had PV. The Feed In Tariff is about 20% of the cost of grid supplied KWh which means that having a battery to cover the period between when the sun goes down and the off-peak rates hit could save a decent amount of money. I would have to gather data (power consumption vs time of day) and do the maths to figure out if the cost savings would pay for themselves though and I am not going to bother to do that without having the option to put up PV in the first place.