A majority of Roblox games are free (because, if they costed Robux to play, then barely any would play, since Robux is scarce to NBCs). However, their developers need to make Robux off their games, so they lead both decent Roblox and (if they have DevEx) real lives and add on to their games more. To do this, they create and sell game passes (which sell permanent perks and cosmetics) and developer products (which sell temporary perks and in-game currency).
Freemium has lived for a while in the video game industry. It's a game structure where you get the basic stuff free, but have to pay real money for the advanced (and usually cool) stuff. Just like in Roblox, it's a popular way for developers to make money off free games. (I still prefer the structure of a paid game and its free and demo-like version, which used to be common a long time ago. I can pay real money for all of the game and don't have to spend any more.)
Let's analyze perks, both offered by game passes and developer products. A perk is a bonus which advances the gameplay, making it faster and easier for the player to win. This includes gaining in-game currency faster, a powerful weapon, and greater health. Look at FuzzyWooo's Shark Attack! for an example. A majority of the gamepasses offer perks, such as "Protective Shark Suit", which allows you to swim underwater without being attacked by sharks, and "Weapons", which gives you long-ranged weapons and a powerful sword.
Nevertheless, perks lead to a common problem, "Pay2Win". This describes the fact that those who pay the Robux do much better than those who play completely for free, despite the amount of skill free players might have. Developer products that offer perks are the most offending, as they are temporary and have to be bought again. Fortunately, some games, usually roleplay/hangout games, such as Alexnewtron's MeepCity, only put a price tag on cosmetic items, allowing all players to experience the same gameplay.
Pay2Win is the reason I'm usually against perks with a Robux price tag. Unfortunately, as the game I'm developing, Animalian Woods, has strategetic gameplay and perks sell well in the community, I'm planning to incorporate gamepasses that boost the gameplay. You have to do what makes the most money, what I value the most, especially since I'm an NBC.
Let's analyze VIP. VIP, offered by gamepasses, gives a set of bonuses (usually cosmetic) for a player to enjoy, such as a custom-music-playing boombox, an avatar editor, and a special name tag. The good thing is that they're permanent, unlike the annoying membership feature Club Penguin introduced and Roblox uses. I adore VIP and plan to use them in all of my games, under different names, since I find "VIP" to be unoriginal.
Thanks for reading this "article" I took my time to write! What are your thoughts? Please put them in your replies. :)