All of those spots you listed in the OP are good but be careful after u3. Ppl scout them alot now. Basically throws are a good option anytime you think the opponent will sit still and block. Mid block string, frame traps, blocked jump ins, after low pokes, after standing resets, after they do something slightly minus, those are all situations where the opponent might want to block. They can still blow it up or tech of course but then you can blow up that too if you read that and that guessing game cycles around and around.
Another spot we don't talk about as much that I like throw is in the mid range neutral game like right outside of jump/ dash distance. If you think theyre going to sit and scout a jump or sit and block projectiles or you think they might try to dash in and start their offense you do dash throw. It also kind of works outside mid range where you're zoning and you think they're about to dash into mid range. You can also dash and meet them at the end of their dash and throw them. Instead of throw you could also just start your offense with dash into block strings in this situation but obviously it won't beat them sitting and blocking.