I can't see your picture, just an "X". However, if you like the insert, then use it...and the fact that you referred to it as a "beautiful" fake insert suggests to me that you like it.
One word of caution relates to future maintenance. I have a fake coral insert, although mine is a fish-only tank. I am able to avoid algae and keep the insert looking as good as new by maintaining good water quality AND a minimal lighting schedule (that part is key). My tank is only lit a few hours in the evening when I'm home, and the minimal lighting seriously reduces maintenance on the insert. If you add real corals, you won't be able to use a minimal lighting schedule. So, in all likelihood, your fake insert will become discolored over time and will become high maintenance. If you will be able to remove the fake insert for cleaning every so often, then you'll be fine (a good soaking in bleach will maintain the insert). But, if you won't be easily able to remove the insert once you add the LR and real corals, then I would advise against using it, since it will become discolored and no longer beautiful after about a year, whereupon you'll likely regret your decision to leave it in.