[calypso]

An app store, watch face store, dictation, weather. those features are the reason it requires a server. That's what you give up by not using rebble or similar services.

[TeMPOraL]

You can sideload Pebble apps AFAIR. I vaguely recall doing that recently to restore the watchface on my wife's Pebble after migrating it to a new phone.

[Wowfunhappy]

You can. It's nice to have a working app store though!

[Wowfunhappy]

Also, any third party apps that create timeline pins unfortunately need to go through a server.