Tim Hardwick, MacRumors:

HomePod can be used as an alarm clock replacement to wake you up in the morning or remind you of something, and soon ‌HomePod‌ owners with an Apple Music subscription should be able to set alarms on the smart speaker that play their favorite songs instead of the default alarm sound.

And:

Changes uncovered by MacRumors in the latest ‌HomePod‌ beta software reveal that ‌Apple Music‌ subscribers will soon be able to do just that.

The beta software includes a revised interface for adding alarms to ‌HomePod‌ in the Home app that provides a choice of playing a tone or media as the alarm sound.

Tiny, welcome new feature. Nice to see HomePod getting more attention. Looking forward to what else the HomePod team has up its sleeve.