[XorNot]

The hardware to manage batteries and the hardware to manage solar panels is different (but sometimes can be packaged into the same box, or with one-off benefits like hybrid inverters), with batteries being considerably more complicated. You would struggle to ruin a solar panel with a bad inverter. You can completely destroy a battery by over-discharging it once.

A solar panel produces energy. A battery only stores it (and loses, round trip about 8% in the process) - which is to say, batteries are solely arbitrage instruments.

[svnt]

You started out loading the whole cost for a grid tie. Now you are talking about a BMS. A BMS is typically included in the cost of batteries.

Batteries are extremely functional in many installations, and even if you’re not using, only selling, arbitrage can work well. This is especially true if you get paid to accept the commodity in one time window and can get others to pay you to take it later.