ESP8266, Arduino IDE vs Lua?
Lua, like many scripting languages, tends to make you a lot more
productive as a programmer: things become far easier as you work at a
higher abstraction level and do not worry about trivial things like
memory management. You achieve the same goals with far less lines of
code. On the other hand, whereas it makes development faster, it also
makes program execution slower. Whether this is a good trade-off or not
is very dependent on the particular application you want to write.

In your particular case, you also have to consider the fact that you do
not know Lua, and you already know both the C++ language and the Arduino
API. Then you may not rip the benefits of Lua on a single project,
because of the time needed to learn the language. You may consider
learning the language as an investment, probably worth it if you are
going to program a lot on this platform, probably not worth it if it's
only for a single, simple enough project. If unsure, I suggest you take
a look at the API provided with Lua on this platform: how well does it
fit your project? Is it a significantly better fit than the Arduino API?