For very good reasons DEFRA do not want new pests and diseases imported into this country. So they are cautious about the import of plants into the UK. There are numerous pests and diseases currently absent from the UK that could easily arrive on live plants, or even the soil in which they are growing and they assess the risks to avoid this if possible.
I had not previously heard of this variety but it seems to be Italian. Seeds if imported with the correct certification and bio hygiene procedure should not be a problem. I doubt they are any more disease prone than any other cherry tomatoes.
Bit like controlling the borders to keep out more easily spreadable and serious covid variants. Too late once they have arrived. And if you are not sure if is more or less severe you keep it out until you are sure.