Your posts did make me wonder, was this really the case, so I run a little test of my own to prove or disprove the theory.
I have no idea how it's done in MTA's source code, nor did I bother to look, but I took it upon myself to find out through real example.
Testing environment setup as follows:
Latest editor definitions from nightly.mtasa, no edits or tweaks whatsoever
Client&Server build: v1.5.3-release-11225
Running resource during the time of testing: none, apart the resource being tested
A map with random 12k objects
No world movement, no camera movement, MTA minimized
Lua map converted with OP's website, without blips attribute (I also highly suggest removing the said feature as it may cause significant changes in performance & loading times) & ran client side
Server FPS Limit: 60
.map is just fine as it is, but .lua allows better manipulation, the very important one being able to load a .lua map with async based on priority, and minimizing client side creation lag or prioritizing other server objects over other less important things
Hope this clears up some of the confusion. Keep in mind this was a very basic test without much fiddling around, if someone could confirm it by doing their own please do.