Can someone explain why people want Sona to be DOTA2 Invoker?

This thought line seems to keep popping up when ever Sona gets some change. And i honestly don't understand it. Does anyone really like the idea of a champion with like 20 different ways their abilities can function? Sure it ramps her skill floor up a ton, but the burden of knowledge is insane. Say QQW is optimal damage output, but WQQ is garbage, QWQ has certain niche uses but can also bit you in the ass if you use it at the wrong time. If you play as her you need to know every combination, how to do you rotations correctly, how to avoid those times where you have "the perfect" combo set up, for damage or healing, BUT you really need to help your ally(s) with one of your other skills.... but that means you can't reset up your combo for 20+ seconds. If you play against her you need to know EVERY combination so you don't get chunked for 70% of your health when you expected to deal with armor pen and a slow. Or we can expand it outwards, you expect a single target chunk and instead Sona busts out something like an AOE explosion that can hit you multiple times (think 's bomb but it applies to everyone in a target area)