1) The impersonator's excellent performance mirroring Cruise's speech, accent, mannerisms, gait, and appearance.
2) The expertise of a professional 'deepfaker', who likely spent many hours generating the faceswap and applying post-production edits.
3) The viewing context of TikTok, where users largely scroll through fast-moving video feeds on small phone screens (hiding some visual flaws in the videos)
Given these limiting factors, highly realistic deepfakes aren't likely to become widely accessible anytime soon.
As @witnessorg's @SamGregory has emphasised, it's crucial that these examples don't overshadow the harms deepfakes are already causing, specifically digital sexual abuse targeting women and the erosion of trust in authentic audio-visual media.