It was intended to be its full operating name, hence the PR about the CROSSRAIL roundel (hence it would only have remained as the tri-stripe logo), signalling and location-coding all using CR prefixes (not E or EL)
EL wouldn't have been available anyway, EL is the prefix for the East London Line signalling.
This ambiguity that TfL have now willingly, knowingly and deliberately introduced between 'modes' and 'lines' is lamentable, but is obviously here to stay. "Crossrail" was NOT originally intended to only be the name of the construction company. It was intended to be its full operating name, hence the PR about the CROSSRAIL roundel (hence it would only have remained as the tri-stripe logo), signalling and location-coding all using CR prefixes (not E or EL) *and* signage being not only designed, but procured and installed. I think we all know the real reason why Boris decided to make this change happen, and I think I can fairly safely say everyone on the outside AND inside Crossrail were taken very severely aback when it came out.
As for that leaflet - that "one sentence" example indicates to me that the leaflet was actually put together by somebody within as a joke, to show the lunacy of the situation, and yet was picked up on to roll out because someone involved in the renaming exercise thought "ooh, that looks good, somebody's done my work for me", with the person who did it being quickly approached by said person and asked if they could use it officially, and the person who did it being taken aback and thinking "phew, I thought I was in trouble".
Exactly! This entire sycophantic renaming shamble has been a disaster, not to mention probably expensive. My only hope is that enough people will keep calling it Crossrail once it opens that they eventually give in and revert to the original name, or at least re-instate the Crossrail prefix.
Whatever the reasoning behind the change, at least we've managed to avoid another different mode of transport being loaded onto the map. The railways are fragmented enough with Underground, NR(and all the various operators thereon), the absurd 'Overground'(which originated in a BR spoof poster campaign in the '70s), Thameslink, et.al., without yet another distinct type of '...rail'appearing.