Cost and fitting time
Panels win on labour. A shower enclosure can be panelled in a day where tiling the same area takes two to three days including setting and grouting. Material cost is closer than people expect once mid-range porcelain is compared with quality panelling, so the saving is mostly time - which matters most on a rental turnaround or a single-bathroom house.
Joints, silicone and the failure points
Panels have fewer joints, but the joints they do have carry all the risk: internal corners, the tray junction, and any cut around a valve. Tiles spread the risk across grout lines that are slower to fail but slower to notice. In both systems, the silicone junction at the tray is the part that needs re-doing every few years.
Cleaning and appearance over time
Panels genuinely are easier to clean and do not suffer grout discolouration. Tiles hold their appearance better against scratching and heat, take a wider range of finishes, and read as a permanent, higher-value finish to buyers. Panels can look excellent when the substrate is dead flat; they show every hollow when it is not.
Repairability
A cracked tile can be replaced. A damaged panel usually means replacing the whole sheet, and matching an older colour or texture is often impossible. If you are specifying for a rental or holiday let where damage happens, that difference matters more than the fitting time saved.