It's complicated and I won't pretend to know all the ins and outs, very few do and clearly no one fully does as we don't have the "perfect" solution. Then there are the patients...
On telling point is that a number of the Ophthalmology papers I have read on the subject basically boil the patient selection process down to "if they ask you how well they will see they aren't suitable".
I have just listed this quote from a random clinic blurb from abroad
"The key to their satisfaction is educating them on what they are going to get and what they are not going to get. I do not like the term premium product. I prefer to say to patients, “Do you want to see far away or up close or both?” ...I think we should get away from this premium idea and instead focus on giving patients varying degrees of vision."
It's a little old (2016) but it's not exactly bristling with confidence is it?
The ray diagrams help a little. Single vision as we all remember from physics
https://i.imgur.com/K8IeOTQ.png
simple enough, light focuses to a point. But when you have incident light (on the L of lens) coming from a near point the focal point will be different so you can't have both in one lens, hence bifocals (just 2 lenses stuck together in basic spectacles) varifocals etc
Multifocal diagrams are way more complex
https://i.imgur.com/LtmqeZJ.png
you can see there is no focal "point" but rather focal blur circles. The spread of light rays at each focal circle gives rise to all the issues blur, haloes, poor contrast etc. It's amazing you can "see" at all from the diagram but you can just not "clearly".
I'm waiting on feedback from one patient who's opinion I trust regarding their procedure but to date I have never come across someone who is fully happy with the vision they have from multifocal corrections and most don't like it. Yes they can see, drive legally and read but the image quality is worse, certainly worse than pre op (or pre cataract if it's a implant) with glasses. But they don't need glasses to achieve that so that's the choice. If your driving force is not to use glasses and you can tolerate the issues, some can, then maybe but most don't and/or can't.
It has to be the future but the issue is always the recipient and it's going to take a long while to come up with a system that pleases all, or at least most. You can't please them all.