An in-line sign-off with a hyphen is a streamlined method for signing off quickly without wordiness or wasted space, all while staying within the body of the message (and instead of using a traditional carriage return).

Source: https://www.dailyeasternnews.com/2023/10/26/column-beyond-sincerely-using-subtlety-to-stand-out-in-the-inbox/

Home Secretary Suella Braverman wrote an article attacking police over alleged bias in favour of pro-Palestinian protesters without No 10 sign-off.

Source: https://www.expressandstar.com/news/uk-news/2023/11/10/sunak-under-pressure-to-act-over-bravermans-attack-on-police/

However, there is a clear sign-off message explaining it will not be used anymore.

Source: https://www.mirror.co.uk/news/royals/prince-harry-meghan-markles-website-31090793

The couple continued: "With this sign-off, we can also, soon, welcome you to our home.

Source: https://www.dailystar.co.uk/news/latest-news/pair-who-mistakenly-bought-derelict-30465286

The only thing White needed sign-off on was the use of the home videos.

Source: https://www.independent.co.uk/arts-entertainment/films/features/pamela-anderson-netflix-ryan-white-b2272101.html

UPSIDE still needs to be inspected by the U.S. Department of Agriculture's Food Safety and Inspection Service and get sign-off from the agency on its labels.

Source: https://gazette.com/news/us-world/lab-grown-meat-moves-closer-to-american-dinner-plates/article_27005e91-54d3-5397-90e3-36e825910d06.html