As a Roblox developer, it is currently impossible to have the script editor indent with tabs. While the subject of whether to use tabs or spaces for indenting is something of a hot topic among programmers, there are people, including me, who prefer to use spaces for indenting. The script editor does not currently support this, and all indents are done with tabs.
I would prefer to be able to indent with spaces, since it helps me copy code snippets in between platforms without worrying about formatting. Other platforms include GitHub, Discord, and any external editors I may use (I write Lua outside of Roblox). It would also be helpful to have support for using spaces instead of tabs, since other platforms often use spaces for indenting (this forum, as an example, doesn’t support the use of Tab to indent) and as a result copying code from them is often a messy experience in the script editor.