Like any vaccination the chances of future infection is less and the symptoms are likely to be reduced due to the immune system being in a better position to react. Therefore the impact of infection is lower, more inline with flu or common cold and therefore a risk that is deemed acceptable. Other precautions, mask wearing, social distancing, reduced travel etc all may further decrease the chance of infection. The UK government seems to have now deferred these additional precautions to individuals and businesses rather than mandate so they and us will have to choose what precautions we are prepared to accept.
The biggest concern from my perspective is the chance of further mutation, the more an infection replicates the greater the chance of mutation therefore if infection rates are still high, even if less serious, then there is more chance of a mutation becoming more resilient. I don't know if this infection is more prone to mutations that are more resilient than others but if it is we may be just pushing the problem further down the timeline, I guess only time will tell.