Map Notes: Why are they so weird?

[AlfredBaldenweck]

Pro 3.5 at the time of writing.

I've noticed over the last few months that map notes are really weird. 

For example, the layer created from map notes was not viable to be used in a spatial map series, even though adding in the polygons directly was fine (now fixed in 3.7). 

Similarly, you can't upload a Map notes layer as a web layer. (Maybe this got fixed in 3.7? I won't be there for at least 4 months)

Today while doing some poking, I noticed the following:

• Background: inside an APRX file, each map has a folder, and within the folder is a series of JSON files corresponding to each layer.
  • They used to be XML files until Pro 3.X
• Map notes do not appear in the map's folder. 
  • Instead, map notes layer appears as a separate folder inside the aprx file.
    • Inside, the layer definition file is an XML, although the contents are actually in JSON format.

So, why are they set up this way, instead of behaving like a normal layer?

[KrishnaDaravath]

Very interesting find. I’ve noticed map notes behave differently too.

Maybe they still use some previous internal structure, which could explain these limitations

[Robert_LeClair]

With regards to a Map Notes layer not being shareable as a web layer - correct - this is not possible.  According to the Help documentation - "Map notes are not supported when sharing as a web scene or web layer. Use the Copy Features tool to copy a map notes layer to a new feature class."
24078: Layer's data source is not supported: <value> | ArcGIS Pro documentation

[AlfredBaldenweck]

Yeah, but like, why? If I add in the datasource directly to the map, it's shareable, so why is the Map Notes Layer so odd?

[Robert_LeClair]

I wish I had a good answer for you, but I do not.  The only "why" I found in support cases are "Map Notes are intended for visualization and annotation purposes only and are not recommended for data that will be shared or used in Web Maps."