There are a number of factors for voters to consider when deciding who to vote for in Local Council elections and one of them is will the candidate actually do the job and attend the appropriate meetings. The attendance record of sitting members is therefore a relevant consideration in the election. See the Cornwall Live item about Town Councillor attendance rates here.
Just because a member has very good attendance does not means they are neccessarily good councillors. It is just hard to be an effective councillor if you are not present at the meetings. Attendance by Penzance Town Council members (2015-16 stats) varies from 27% to 100% . An attendance over 80% is good, below 60% is a problem. There can be extenuating circumstances with health issues or caring responsibilities but if the problem is ongoing then the member should resign and let somebody else stand which is what Cllr Lewarne did when her otherwise good attendance record fell due to caring responsibilities.