Looks like its a deal with the Euronics chain. So those shops that previously sold TVs with only the standard 1 year now will add it up to 5 year if you register within 90 days with Samsung. Potentially could broaden peoples shopping choice right now if buying an outgoing 2020 model in their applicable list.
Although 2021 models are still too expensive to consider buying, and most other shops sell their TVs with 5 (6 in the case of Richer Sounds) years warranty anyway.
Doesn't seem to have anything to do with their own online store, which has always been a 1 year warranty.