What do you need xbox live for and what xbox live Gold and these other things for?
Play online.
Xbox Live Gold - so you can play online and you can even download a few selected games for free
Xbox Game Pass - you have over 300 games for free as long as you have an active subscription.
The main reason is to play online.
Xbox Live itself is an online service that is required for a number of Microsoft games or services in order to use them. An example is Minecraft on Android, PS4, or Nintendo Switch, where you mainly need an Xbox Live account to play online. The same is needed for some games or services on the PC. In crossplay games, however, you have to be careful that there are different requirements for different platforms in the same game. Be it the membership of Nintendo Online, PS Plus or others.
Xbox Live Gold has been a subscription model since 2005, which allows you to gamble with other players. This service is only required on Xbox 360 and Xbox One, and costs monthly, quarterly, semi-annually or annually, around 6.99 euro, 19.99 euro, 29.99 euro or 59.99 euro. With gold membership you are mostly protected * and you even get some discounts. If games are already discounted and you get a gold discount again, the games are relatively cheap to get. As a gold user there are also 4 free games available every month. 2 games are Xbox Classic or Xbox 360 titles that will remain in your possession forever when you purchase them as Games With Gold (short AMLA). With the 2 Xbox One games, the games are only available until the membership expires or the Xbox is offline for 24 hours.
Game Pass is a subscription model in which you can borrow just over 100 games. The concept follows that of Xbox One Games with Gold games, only that they run in the Game Pass version. So don't lock them if Xbox Live Gold expires. Although Xbox Classic and Xbox 360 games are included in the Gamepass, this service does not work on the Xbox 360 console. The subscription model is only available for Xbox One and PC.
Game Pass Ultimate is a combination subscription consisting of Xbox Live Gold and Xbox Game Pass. This subscription model is the most expensive, but most lucrative, that Microsoft has to offer. However, this subscription model only makes sense if you have a PC AND an Xbox One. As Gamepass Ultimate already contains Xbox Live Gold, which is only required on Xbox. Although Xbox Gamepass does not work on the 360, you can continue to use the Xbox Live Gold service. Gamepass Ultimate auxh is therefore only available to a limited extent. So; Ultimate works on: Xbox 360 (limited), Xbox One and PC, but the main focus is the Xbox One.
I hope I could now answer your question in detail.
Cheers ✌️
* protected: any situation can lead to the protection of the Xbox Live network no longer taking effect. This includes:
Xbox 360 consoles in general, since there are more modders whose consoles also have integrated DDOS programs, Xbox 360 users are not safe with online games.
Xbox One, you can be exposed to a DDOS attack if you join a strange party or reply to a strange Xbox Live message.
Xbox Live security on Xbox One generally does not work when playing crossplay games, especially against PC players, can also lead to unexpected if not major problems.
