The difference is that these documents are very fleshed out, reading more like a SMPTE document than a brief one what one should consider, and are complete with Normative References and a Glossary, in addition to the required formulas and charts.

Interesting highlights include the luminance parameters for 500 candela/m² (146 fL) with stricter tolerances and roll offs at the edges and corners. A minimum black level of 0.005 cd/m² is specifically mentioned, which is a 5 decimal point swing, or 100,000:1. It was nice to see that P3D65 makes an appearance as the White Point, coming on the heels of the latest revision of ST 2067-102:2017

SDR ranges are also specified, with a black level under 0.01 cd/m² being the level under which the display shall never reproduce. This might protect grey fuzzies from appearing in place of blacks in SDR releases shown through HDR machinery. References to 5,000:1 for SDR are mentioned in the Direct View Display document, but not the HDR. In fact, there is an actual paucity of the word Contrast, though not a dearth…it is mentioned once and implied a few times.

High Frame Rates are also detailed in the Direct View document, in Edit Units per second. 

Many other details…go to:

DCI DRAFT High Dynamic Range D-Cinema Addendum version 0.9 (PDF) 
Click here: http://dcimovies.com/drafts/DCI-DRAFT-HDR-D-Cinema-Addendum_v09_2018-1116.pdf

DCI DRAFT Direct View Display D-Cinema Addendum version 0.9 (PDF)
Click here: http://dcimovies.com/drafts/DCI-DRAFT-Direct-View-Display-D-Cinema-Addendum_v09_2018-1116.pdf