Choose the device around the part of the experience that must be public and the part that should be personal. A large screen can show a race, a comparison, or a shared result. A visitor's phone can carry a private answer or allow them to continue after leaving the station. Neither surface is automatically the better event experience. The choice changes who can start, what bystanders can see, and what happens when a visitor does not scan a code.
Research helps frame the trade-off, with clear limits. Petrelli and O'Brien compared a phone app, smart cards, and smart replicas in a museum study with 76 participants who tried all three. The phone was the least liked mode in that study, while tangible card-and-replica interaction was most liked; the phone aided mobility but drew attention away from the exhibition. This was a museum content experience, not a commercial event conversion test. Petrelli and O'Brien, CHI 2018 conference abstract; Sheffield Hallam research record.
In a different public-display task, Alt and colleagues compared direct touch and phone-based ways to create and retrieve notices with 20 laboratory participants. Direct touch had the highest usability; participants also valued using phones to enter information more privately. The study concerned a notice board and cannot give a turnout forecast for a brand activation. Alt et al., CHI 2013 paper.
Split the job before choosing the device
Write one sentence for each step: attract attention, start, make a choice, show a result, and take something away. Then ask which steps need a shared surface. If spectators must understand a simulated product, the venue screen needs a clear public state. If a visitor must enter a private email address, doing so on a large public display may expose it to people behind them. A mixed design can place the demonstration on a shared screen and the optional personal handoff on the visitor's phone. That is a design hypothesis to test, not a prescription from the studies.
Consider the failure paths. A phone route asks a guest to have a device, enough battery and connectivity, and willingness to open a link or QR code. A kiosk route asks the organizer to manage a shared physical station, turnover, cleaning, and data reset. An event can offer an assisted or non-phone route for the essential experience without forcing every visitor into the same device. The public kiosk reset guide covers the separate handoff between users.
Prototype both starts
Build the smallest working first minute for each option. Put a printed or on-screen link where it would actually sit and invite first-time visitors to begin without explanation. Record where they look, whether they scan, how long they spend getting to the first meaningful action, and whether they can finish without a staff rescue. Do not compare only the number of scans: someone who never starts is part of the design result.
Test a group as well as an individual. A phone can isolate each person in a private flow; a shared screen can make the action visible to friends. The group turn-taking guide addresses roles around one screen. Finally, test the route with the venue network unavailable or slow; the offline fallback guide covers the operational plan.
Choose the surface that lets the intended visitor complete the intended task under event conditions. Record the reason in the brief so a later preference for a more impressive device does not quietly change the visitor outcome.