The ELR was really just a first attempt to see if there were some "early-adopters" out there among Cadillac buyers. It seemed to exist in brochures and online, but few dealers had one or could get one. Also, because of its rarity, most dealers did not want to invest time time and money into getting their service personnel trained on serving an EV. The CT6, on the other hand, is being produced in China to meet market demand and regulatory requirements for GM to be a player in that very big market. Cadillac maintains its status and cachet in China and, from what I have heard, the EV version of the CT6 has been well received. As a long-term Cadillac owner, I would have loved to have the option of buying a competitive Cadillac EV, but if I were going to spend that kind of money on a luxury touring sedan, I'd have chosen the Tesla S which has all the creature comforts, technology, and a practical EV range. Cadillac is making some very nice vehicles these days and is recapturing its previous reputation for design and quality. Tesla has proven that there is demand for a luxury sedan; it's only a matter of time before Cadillac will have to participate seriously in that market niche to maintain its brand.
Interesting. Historically, Buicks — black Buicks — have had a following in China for a long time. https://www.google.com/amp/s/amp.cnn.com/money/2017/02/22/news/companies/buick-china-history-brand/index.html