Offline play is not even biggest issue - legality is however and Spotify themselves have made it very clear on their forums that public performance can get your username blacklisted.
"it is no longer possible to purchase tracks through Spotify as mp3’s as the downloads store has been recently removed from all countries… there are no current plans to restore it. "
I think that answers your idea about buying a tracks from Spotify. However its something that would render using Spotify in the first place pretty useless anyhow. May as well just browse Beatport or iTunes right ?
Negotiating and adding buttons to buy tracks when you are already paying for streaming services, is just a workaround and NOT a real solution for a Pro DJ use with “Pro” labelled software when the current (Pro software) competition are all (except NI) implementing Pro level streaming services (sry, lotta pro’s in there).
Personally I’d prefer a Pro Spotify plan, but if the solution is waiting/hoping for them to implement something vs writing something that WILL work, is it not better to have the alternative option before people jump ship ?
FYI - Peeps need to vote for “Spotify Pro” if its ever going to be considered here: