If you're an iPhone user, you can use the built-in timer in iOS to get the same effect. Spotify can't play song until you allow in phone app.
From Spotify:
Playlists are a great way to save collections of music, either for your own listening or to share. To create one: Tap Your Library. Give your playlist a name. Start adding songs (and we’ll help you along). Master Spotify with these tips. Photothek via Getty Images The recently updated Spotify Premium boasts a streamlined design with only three buttons at the bottom of the app for navigating its wares. Due to various technical challenges, the Playlists feature has been removed from the Roku Spotify app. It's just too hard, I guess. Interestingly, their Spotify Gear page lists 135 devices that Spotify would love their customers to use to stream Spotify. Spotify was founded in 2006 in Stockholm, Sweden, by Daniel Ek, former CTO of Stardoll, and Martin Lorentzon, co-founder of Tradedoubler. According to Ek, the company's title was initially misheard from a name shouted by Lorentzon. Later they thought out an etymology of a combination of 'spot' and 'identify.' Early international launches. Former Spotify headquarters in Stockholm.
Spotify Roku App Update
Due to various technical challenges, the Playlists feature has been removed from the Roku Spotify app.
Add Spotify To Roku
It's just too hard, I guess.
Interestingly, their Spotify Gear page lists 135
devices that Spotify would love their customers to use to stream Spotify. Roku is not one of them.