As per article it’s because of the day job who doesn’t leave too much time handling those and that the video making is a hobby to him - I read from it he doesn’t want to make it a job?
Assuming everything else remained constant. I've seen creators comment that adding sponsorships really hurt their growth numbers.
Someone who is reviewing tools could be hurt by getting sponsored by a tool brand, because of the obvious possible conflict of interest.
But that same person getting sponsored by one of the damn VPN providers might affect it less.
It also depends on where they put the sponsorship and how easy it is to skip.
I do see other tiktokers do it poorly, like having a long lingering shot on the label that makes you realized the video is an ad. Somehow they still get views but their videos are really really boring.
But this model doesn't apply to every channel. If I'm on a science/physics channel, I'd tolerate scientific/test equipment sponsors but that's rarely what we see (turns out most quality goods sell fine without polluting YouTube videos), so instead you get VPNs, crappy Chinese earbuds, website builders, etc.