Yes, that’s in their regs. Must have a switch on the roof. Also one of the things that ironically caused a few roof fires. Some switches were said to comply, but didn’t, got recalled, etc etc. Dave himself has a video of a roof-mounted switch full of water.
I would not say that is a new trend. Micro inverters have been around for almost a decade now. I remember looking at them back in 2013, because I thought they’d make a good (if somewhat more expensive) way to add solar incrementally, one panel+inverter at a time. I believe the one I looked at back then was a Taiwanese brand called APsystems.
Sharp also made “AC” PV modules that had a built-in microinverter as early as 2011.
Also, Enphase is arguably the market leader when it comes to this, but they don’t even have a footprint in SA… at least not one to “write home about”.
If anything, the craze died down a bit.
In my opinion, the microinverter solution suffers from the same problems as the SolarEdge “optimizer” solution. You’re placing the inverter (or part of it in the SE case) in a very hostile environment, right below a very hot PV module. That means more expensive components, and a higher failure rate. Even with low failure rates (say 1 in 500), because you have multiple inverters in the installation, the odds of a single failure multiplies by the number of inverters.
Unless you have a big problem with shading, which requires panel-level optimisation, I would still opt for a string inverter (as they are called) downstairs rather than several small parts upstairs.
Edit: Also, as other posters have said, in SA we kinda want backup. And most microinverters do not support frequency-dependent power reduction. Or at least they didn’t the last time I looked. I think Hoymiles have one now that does…