Spotify free version has ads, but Spotify premium version is ads free.
Ads can be disabled on web buy ad blocker extensions and other software, this may be the reason spotify may care less about the web player than they do about the downloadable application
Spotify web player may sometimes not work in your browser.
I have added common problem with their solution.
Spotify Web Player Not Working on Safari Browser
Spotify users on the service’s Web Player have noticed that they can no longer listen to music in Apple’s Safari browser, taking to Spotify’s Community webpage to discuss the incompatibility between Safari and Spotify’s Web Player
Users on Spotify’s community noticed the change earlier this week when they attempted to open the web player in Safari. They received a message that informed them that the browser no longer supports the Web Player, and directed them to another browser or the desktop player.
The company’s system requirements page now states that it only supports Chrome, Firefox, Edge, and Opera. A customer service representative confirmed the change to the forum users, saying that “after recent updates, Safari is no longer a supporter browser for Web Player,” and but wouldn’t say “if or when any specific features will be back.”
Spotify Web Player Unblocked
You can unblock Spotify web player using VPNs
There are many free VPNs like tunnel bear which is giving free 500 MB every mont ,
you can also use snap VPN and Nord VPN