Entities, columns, and option sets have two names in CDS and SharePoint:
Logical name: the concise, unique, unchanging, no spaces, no punctuation, hard to read name that is used at the API level. CDS adds a random publisher prefix to custom names that is particularly ugly.
Display name: the long, non-unique, easily changed, localized, sure use spaces and hyphens, easy to read names that appear to end users in the apps.
We recently switched to using Display names for CDS and SharePoint. During the Preview period, there was a switch to change back to using Logical names. Very few authors used this switch. Still some in the community voiced their desire for Display names to be optional and asked us to keep the switch.
We are trying to keep the permanent switch count as low as possible. There is only one today: the non-delegation record limit. A multitude of switches makes debugging an app harder especially when reaching out to someone else for help; the first thing that has to be done is a careful review of the switches. We're better off if the experience is consistent across apps.
Note that you can still use logical names in formulas. We won't advertise logical names in the formula suggestions, but they can still be used. These formulas, working with the standard Accounts entity in CDS, refer to the same field, first with the display name:
And using the logical name:
After much debate we ultiamtely decided to remove the switch for now. I have created this idea to capture votes to bring the switch back. If you feel strongly about first class support for Logical names please help build the case for bringing the switch back.