I have been using TB for about six years. I feel it is an effective tool to help measure the overall SEO quality of your video. However, in the last few years, SEO itself has become almost irrelevant, as the new algos use user Engagement as the primary source for measuring the worthiness of a video, not the SEO. Modern AI driven aglos focus heavily on Bing-Worthy Content (BWC) over quality and substance. The platforms push and promote content that encourage users to doom scroll, rather than actually trying to server the viewers with content that they actually want to see. User now have to battle against the algos to find the content they actually want, while the aglos bombard them with an endless array of viral BWC in attempt to keep them watching and search for what they actually want. The platforms know that if a user finds what they really want, they will be satisfied and leave, so they play a game of keep-away with their users, giving the clickbait BWC content, instead of what they know the user wants.
Before this switch to AI driven BWC engagement algo, my channel was very successful. If a video was underperforming, I could use TB to work on improving the SEO and see almost immediate results. However, now, my experience has been that using TB to improve the SEO of videos has literally zero effect on video performance, because YouTube use a User Engagement metrics to decide what to promote, not the SEO.