The measures would include additional publicity generated in established and new media sources. There is also significant value in drawing attention, eyeballs, and new prospective customer segments to your niche sport within a rare dead air night in the highly busy, lucrative fall time that includes NFL football, MLB World Series/playoffs, NBA regular season start, and college football. (And those are just the major North American competitors).
The risk is minimal with an establish customer base whose usage pattern is often focused deeply on one team or deep, passionate fans that are little risk to lose over a content gap of 1 nightly game before and after the big promotion. There's also quite likely established die-hards who like the full day binge of hockey watching and teams they might not care for or see out otherwise.
This is a strategic marketing bet to future potential and growth to elbow a critical tiny window of exclusive profile across a deeply competitive market with bigger, more established competitors. The NHL is in fact 'growing' the game with record revenue and among its marketing strategies one can include expansion, big spectacle events like Frozen Friendly and Stadium Series, and global outreach to established hockey countries and barren ones with prospective new audiences. The disgusting gambling relationships also reflect the proven correlation between watching sports content and gambling.
NHL marketing is quite far reaching and more sophisticated as some might think. It's just not pointed at the established customer base which is already bought in and leveraged with its offerings whether viewing, attending, and/or buying shit.