I asked same just a few days ago here. For the record, I ordered Zigbee since I have strong mesh for either in the location, and I couldn't see spending an extra $20 for Z-Wave. I've had mixed results with Matter devices, so wasn't quite ready for that.
I would assume that blackout shades and blackout cellular have the same degree of blackout. Cellular would give a little better sound/heat insulation. I went with shade because we have it behind window treatments. I know shades slide well behind them as that was what we had there before.
As I noted in the other thread, buying from ShadeWings direct gets a third year of warranty that costs extra if bought on Amazon. Cheap people like me uncovered 2% rebate on topcashback and also a 5% promo code via google search.
