I just realised, in order to unlock Master Chao you HAVE to spend Robux for it.
Think of it like this, say you don't care much for chao in Speed Simulator but in past events chao were still given to you as part of the event. Such as the Strawberry chao or the Knuckles chao. These chao go into your inventory where you can only have up to 20 chao.
In order to unlock the Master Chao, you need all twenty chao available on Green Hills. So not only are you spending your rings for random chance of getting the chao you want, but each chao is taking up space in your inventory. If you never partook in any events before Master Chao event then you'll have twenty space for all twenty chao in Green Hills. But if you already have chao like I already do, then you must either delete your event chao or spend robux in order to expand your inventory.
And it looks like the Metal Sonic event involves "Electric Chao" so if this is the direction Gamefam will take with Sonic Speed Simulator then I just won't get involved in any chao-related events if it uses underhanded methods to force us to spend Robux.
Honestly, it would just be easier to just wait unto the Master Chao has it's own Robux price and buy it directly then than standing around vendors playing this stupid lottery game.
Can't believe I'm saying this, but I'd rather be running around collecting stuff than just standing next to vendors with this stupid lottery.