According to Qichacha https://qcc.com/firm/95c92bca98e4e1935b982fb6c4e865f6.html , the 1% stake was acquired by a fund http://www.ciifund.cn/ set up for strategic investment to support companies in the internet sector.

Putting 2 million RMB into a Bytedance subsidiary at this stage is unlikely to have much impact in the sense of the fund's original mission, but if the investment performs well, it'll likely contribute to the income of various people involved with the fund.

It may not make much sense if you think of the government as a monolithic entity, but if you consider that it's actually a network of self-interested individuals, it's not all that surprising.