Personalisation in hospitality gets talked about vaguely and implemented shallowly. Putting a guest's first name on an email is not personalisation; it is a mail merge.
A personalised menu means the guest sees genuinely different content, in a different order, from the guest at the next table.
The most impactful and least glamorous. A guest reading the menu in their own language orders more confidently, asks fewer questions, and is far more likely to try something unfamiliar — because the risk of ordering something they did not expect drops.
In cities with international dining rooms this single change often does more for average spend than anything more sophisticated.
Flagging allergens is compliance. Reshaping the menu so a coeliac guest sees what they can eat rather than a list mostly full of things they cannot is personalisation.
The difference matters commercially: a guest scanning a long menu for the few safe options usually settles for the first workable dish. A guest browsing a menu already filtered to their needs chooses properly, and chooses more.
For returning guests, what they ordered before is the strongest signal available. Not to repeat it endlessly — a guest who always orders the same thing does not need reminding — but to recommend adjacent to it, which is exactly what a server who knows them would do.
Being visibly creepy. Guests are comfortable with a menu that adapts and uncomfortable with one that announces how much it knows. Adapting quietly is the right posture.
The other failure is over-narrowing: showing a guest only what they have had before removes discovery, and discovery is where higher spend comes from.
Would a good server, who had served this guest before and spoke their language, do this? If yes, it is personalisation. If it only makes sense to a marketing system, it is not.