Well, in the Toledo at least with a space saving spare wheel the main floor is flat, no bumps or lumps anywhere so the false floor is not required to flatten the floor surface.
The main purpose as far as I could see is to kill road noise, as there is no noise reduction padding under the boot floor carpet.
If it was so uniquely useful, why do you think SEAT as dropping it ?
Maybe because like other 'novel' ideas which were introduced with the Altea / Toledo, SEAT are quietly dropping them as they are being recognised as no more than a crazed designer's quirky experiments which have no real use other than filling up marketing blurb in the brochures......eg: the puncture repair kit instead of a spare wheel (RIP thank GOD), that stupid reversing light under the bumper / behind the rear wheel...thankfully gone on the Altea XL, in fact the entire Toledo rear end which is quitely being replaced by the Altea XL itself.
I don't mind anyone saying that they have found a use for the false floor, I am just pointing out that for a lot of buyers, it is the full sized boot that attracts them in the first place, and it is that total volume that SEAT crows about in their blurb about how much luggage space you have in the boot. If someone wants to go out and buy an optional extra false floor to split this in two, so be it...but the majority probably dont want it and wont use it. For instance, you cant get a full size pram into the boot with shopping with the damned thing in.
Question: why dont other cars (including SEATs) have a false floor if it is so revolutionary ? Surely
Ibiza buyers would be queueing up to purchase one ??