Every choice has tradeoffs. For me, what the lemon oil offers is replenishment of the heavy turpines that evaporate from the Ebony as it ages. This keeps cracks from forming. Some people are sensitive and may even get contact dermatitis from lemon oil, so those people should not use it. Will their fingerboards crack off their Alembic? No. Frankly even if you never oil your fingerboard you'll probably be okay if the instrument is kept where people like to be, but it will likely develop cracks at some point which are 100% repairable. Even with regular oiling, you will likely have cracks at some distant point in the future.
I have heard horror stories about over-use of lemon oil that frankly would probably have the same result regardless of the the oil used. Most are with petroleum distillates with scant lemon oil for scent, but still, lemon oil gets the credit. No guitar wants to be bathed in the stuff!
However, I suggest you take care of your fingerboard with whatever makes you happy. If it's a commercially marketed fretboard cleaner - great if that works for you. If it's lemon oil, awesome, I know that stuff works well. If it's olive oil, well, I'll think fondly of our old friend Paul. Like to use lighter fluid to clean it up? Well okay if that's your thing (but stinky!). The important part is to inspect your fingerboard regularly and react to changes and little problems before they become a big problem.
Note that my recommendation for pure lemon oil is for conditioning the board. Only a few drops is needed if you do it once a year. Our fingerboard have no finish on them other than lemon oil, so you're free to use whatever works best for you.
