What is the benefit of using Photos over iPhoto or Aperture?

Photos is much better at sharing across devices (iPhone, iPad, Mac) than is iPhoto. It's really good at keeping all your photos accessible on all your devices; it's great if you take a lot of photos with an iPhone, and you want them to "automagically" show up on your Mac. You can also sync all your edits between everything instantly.

Its ability to adjust photos is on par with iPhoto. I'd say, it's a perfectly good replacement for iPhoto, as in nearly every way it's as good or better.

Aperture is a very different beast. Aperture's organizational abilities and image adjustment abilities (with curves, local adjustments, etc.) were far beyond what Photos offers today. If you're a serious amateur or pro photographer and really leveraged Aperture, then Photos is a big step backward. But for 95% of users, it's probably not.

No they most certainly are not all the same

THe simple answer is that Photos is supported and has a future while iPhoto and Aperture are dead products with no support and have no future

Photos is a much better program than iPhoto - a few drawbacks but mostly advantages - Photos does not come close to Aperture - Photos ia a consumer program and Aperture a professional one

The differences between Photos and iPhoto are listed here - Photos 2.0 vs iPhoto 9.6.1: Features and Capabilities

LN

Both iPhoto and Aperture are at the end of their life cycle. Apple stopped the development and is no longer selling them from the AppStore. The current versions Aperture 3.6 or iPhoto 9.6.1 are compatible with MacOS X 10.11.4, but there will be no future updates. And Apple announced, that it will no longer be possible to order print projects (Books, Calendars, Cards) from Aperture or iPhoto after the end of the month.

It is too late to start using iPhoto or Aperture now, if your Mac is running MacOS X 10.19.3 or newer, because you will not be able to purchase compatible versions.

Photos for Mac is Apple's first Photo application, that allows to sync a photo library across several devices, and not only between Mac and iPhone or iPad. I am using it to keep my Photos Library in sync between for Macs. Editing is easy, and the photo editing extensions make it easy to use third party photo editors.

What is still problematic, compared to Aperture or other professional digits asset management software, is the lack of support for a customized workspace and batch processing. The user interface does not allow to customize the tools and in many cases is it not possible to apply commands to multiple selected photos at once. So editing is much slower than in Aperture. And not all EXIF or IPTC metadata can be accessed in Photos.

See OT's User Tip:

Photos 1.5 vs iPhoto 9.6.1: Features and Capabilities

FWIT simple EXIF viewer works with external editors for Photos so I can see all of the Metadata - it does not edit the metadata

LN

I'm missing the ability to create metadata presets for different purposes and to use all metadata in projects - o webpages, in slideshows, in books, below the thumbnails or in list view. And most particularly in smart albums.