The original version had a typical incubation period of 5-6 days, range 2-14, which was why SI was first set at 14 days, reduced to 10 to improve compliance (with some risk, but most cases would have shown up by 10)
If this variant can have a longer incubation period, then our SI might be inadequate
That might be a factor in why officials and politicians sometimes sound concerned. That plus the rate it's rising.
Even if the rates of death and hospitalisation are low (vaccines preventing serious illness, the young tending not to get it seriously anyhow) it could make a lot of people unwell in a short time, which wouid in itself be highly disruptive (lots of people off sick for a fortnight)