The first 30 second CM quickly establishes Junichirou's character: a dark room with only the computer monitor as a source of light, nothing but posters and figurines around him while he's rejoicing over something and being obstinate over getting job. This dorky image set up is just as quickly broken by him asserting his sudden want to become a teacher to help a student prove to a stuck-up twin-tails that her job and passion shouldn't be looked down on. Kagami's values and morals are very evident even with the short time it had.
A big part of what helps sell this rendition of the main character is Daisuke Ono's performance: as much as Hiroshi Kamiya performance of him in the tv anime is good to the point of being the only positive aspect of that adaptation, Ono doing a voice similar to Battler from Umineko fits Junichirou's childish but badass personality fits him perfectly.
That performance is what makes the 2nd commercial lasting only 15 seconds to be so memorable. This moment showcases the main character and the narrative's ethos of "only doing things you want to do" which is essentially the series defining scene and payoff to his year of being a teacher. It's obvious only the people who've read the manga will understand the context behind it, but suddenly starting off with Kagami being on a really high roof preaching with a mic helps sell his eccentricity and give a sense that this speech is important.
