There is clearly room for everything on the platform. The worry is when content which clearly lacks depth, originality and polish is receiving distribution that would normally correspond to genuinely striking and thought-provoking content.
As I say, medium struggles at the best of times to effectively distribute its existing content. If the underperforming distribution system is swamped by a mass of recently arrived users for whom it is the new fun toy, that could have implications for the visibility of more conventional writing, which aims to achieve far higher levels of originality, insight and stylistic accomplishment.
Other writers have drawn attention to this phenomenon in various ways and from various angles.
Seeing this mass influx via TikTok championed and swooned over by Medium staff raises question about the platform's intended direction.
Medium was originally intended as a more thoughtful, deeper, longer-form alternative to wham, bam social media. Inevitably it has evolved and expanded in many ways, but I don't think it is well suited, philosophically or technically, for a shallow, short-attention-span, trend-led style of content and distribution borrowed from other platforms.
If that begins to dominate feeds more widely, I believe it would be a problem for many long-standing users.