When I forget to sign in to YouTube, I see the same pattern, shitty ads that are clearly only allowed because otherwise YouTube wouldn't have sufficient ad inventory to meet their internal KPIs.
Nah, they advertise (probably) for a similar reason as car brands do, to make the people who bought it already feel better and more reassured about their choice.
Also, obligatory "lucky 10k" xkcd: https://xkcd.com/1053/