My opinion is that the only people who should be applying ED are the ones who aren’t asking financial aid questions.
If your kid has a clear favorite, you can afford it, then apply ED and potentially be done.
That’s not the case in our house, so we had D1 apply EA (nonrestrictive) to as many as she was willing to do the application for. Like others have mentioned, merit is often only available during the EA round.
We also wanted her to be able to have the luxury of applying RD if none of the EA applications worked in her favor.
We have X amount of dollars saved for each kid. How they want to use it is up to them-D1 chose not to go deeply in debt for undergrad and to go with one she loved that had great merit vs one she loved that had good merit but was much more expensive. She had the luxury of pondering this choice for several months since she’s known where she got in EA/