Super Mario Party isn't promising.
A new update for Super Mario Party has finally added the ability to play the game's main game mode online. For over two years since its release, players were only able to play select mini-games with family and friends in another location. Having the traditional Mario Party mode playable online is a big step for the series, which hasn't had online functionality in any previous titles. However, the lack of online multiplayer at launch was a bit of a mystery considering the prevalence of online gaming.
So far only two game modes have been confirmed for Mario Golf: Super Rush: a new story mode, and Speed Golf - the latter of which has already been confirmed as playable online. If Speed Golf is the extent of Super Rush's online functionality, it will be seriously disappointing, and a major detriment to the success of the game.
Poor Online Functionality Could be Detrimental to Mario Golf
It is probably safe to assume that a normal round of golf will be playable online in Super Rush, since it isn't as complicated as Speed Golf - a game where all participants take their shots concurrently. However, the idea of Nintendo metaphorically dropping the ball on Mario Golf's multiplayer shouldn't be completely dismissed, considering Nintendo's widely disliked online platform and the aforementioned belated integration for Super Mario Party.
Mario Golf as a series doesn't quite have the name recognition that Mario Party does. Despite widespread criticism for lacking online multiplayer, Super Mario Party managed to become a best-selling title for Switch when it released. However, a bit of negative press probably can't affect a popular game like Mario Party like it could Mario Golf.
With the large Switch base, there might be many people who have never tried a Mario Golf game, and a bad review or lack of important features like being able to play online might turn newcomers away from a game that could otherwise prove to be very popular. Super Mario Party was able to succeed despite the lack of full online play, but Mario Golf: Super Rush will need as many gameplay options as possible to modernize the series.