When comparing PICO-8 vs Roblox Studio, the Slant community recommends PICO-8 for most people. In the question“What are the best 2D Lua game engines?” PICO-8 is ranked 4th while Roblox Studio is ranked 11th. The most important reason people chose PICO-8 is:
Because it's an all in one product, you don't have to worry about things like how to load sprites.
Specs
Ranked in these QuestionsQuestion Ranking
Pros

Pro Takes away the pain of having to wire things together
Because it's an all in one product, you don't have to worry about things like how to load sprites.

Pro Very simple programing language
It's lua with a few modifications.

Pro Encourages building simple games
As a beginner it's all to tempting to try to make the games you like to play, like Zelda or Call of Duty when we should probably be making pong.
Pro Restrictions of tokens count "forces" to write code effectively
When you reach 8192 tokens, you're screwed. However, this limit can teach you to take a look at entire code and think how you could optimize it.
Pro Possible writing code in external editor
Since launch of 0.1.12c version of software, you can now write and include external script using the same directive just like in C / C++.

Pro Perhaps one of the easiest sound editors around

Pro Share the game in a .png file with other Pico-8 users

Pro You can read the code of any game you play

Pro Lots of examples
Almost every game made for the Pico-8 is open source (if you can download the .png, you can see the source).
Also there's the fancy Pico-8 "fanzine" that has lots of code examples as well as other great tutorials in a beautiful physical or PDF form.

Pro Easy to get things going very quickly
Pro It's easy to use
If you want to find an object in the workspace just use workspace or game. In Unity (for example) it's much more complicated.
Pro Easy multiplayer
Multiplayer is set up on project load.
Pro Easy to use for children
It's the entrance to game development. But it will be likely, that you abandon Roblox as soon you turn old enough.
Pro AI Scripting
Pro No serverhosting required
Pro No website needed
Roblox hosts a very basic website to play your game for free.
Pro It’s fast
Scripting can take maybe only 30 minutes to get some real work going while others take hours.
Cons

Con No collision library or other common things
Pico-8 is very minimalistic and as such doesn't come with really any abstractions whatsoever which means often you end up re-inventing the wheel.

Con Code editor leaves some things to be desired
Such as code completion and automatic indentation.

Con Costs 15$
Unlike many of the other frameworks it's not free. However this is kind of a feature because it means it's much more likely to be supported.

Con Memory restrictions could be confusing or frustrating to a beginner
Con No support for Linux
With the new-Bit client, Roblox went out of their way to make it impossible for Linux users.
Con No tutorial system in place to teach new dev's the basics
Con Can only be published on Roblox
You can't export your game to Steam, Epicgames, Snapcrft or Flathub.
Con "Potato Servers"
Roblox Servers aren't that good in performance. Also, a server can officially only handle 100 players at the time. They tried 200 player severs, but abandoned this idea.
Con Players need to be online at all times to play your games
Con Can't selfhost servers
You can only use the Roblox servers.
Con Can't post links in games
The Roblox TOS only allow Links to certain platforms like Guilded.
Con High tax rate
Be ready to give 75% of your earnings to Roblox.
Con Bad moderation system
