I would imagine that a clinical examination and swab is considered best practice, the aim is to reach as many women as possible so self swabbing is a way of including women who are reluctant or refuse a clinic based examination.
Basically a self administered swab is better than no swab.
A significant percentage of women refuse breast screening, there are alternatives but they are expensive. Ultrasound and ct/mri scans can be used but they take longer and cost considerably more. Mammograms will not pick up every cancer but they pick up 30% of all women diagnosed with breast cancer. The rest are either as a result of self examination or incidental finding during tests or examination for other problems. Without early detection the cost to the NHS and patients families would be much higher. Stage 4 breast cancer can, in some cases, be treated palliative for many years but the drugs used are very expensive and prescribed on a case by case protocol. Stage 1& 2 are predominantly curable ( that is they are treated with the aim of them not recurring or a recurrence is expected many years later), mammograms often detect breast cancer well before a lump is palpable and before the cancer has spread.
My breast cancer was just palpable ( it felt different), I noticed it a couple of weeks before my routine mammogram so wasn’t surprised I was called back. It was already 39mm in size, so the size of a small egg. It was only 100mm from the surface of my breast. I was really surprised how big it was and how difficult it was to actually feel. If I hadn’t lost weight it may have been months before I felt it but the weight loss made it more prominent. I never missed a screening mammogram and self examined monthly after my DSis was diagnosed at a young age. My DSis was tested for the BRCA genes and was negative so we were not seen as high risk. Mine developed post meno after 4yrs of taking HRT, even with two of us in the family we are still not considered a genetically high risk our breast cancers were very different. Basically we were just unlucky.
Screening saves lives and gives other years extra even if diagnosed late. Breast cancer is still increasing, there are many possible reasons for this, probably the most common is that we are living longer and cancer is a disease of aging cells.
Hopefully, with vaccination and HpV screening , cervical cancer will become an uncommon cancer, and women can feel a little less anxious about developing it in the future.
I will be eternally grateful to the breast screening service and the cervical screening service. I may not have had cervical cancer but the fact that I was screened every 3-5 yrs throughout my adult life has reduced some of the anxiety.
Hopefully, the future will bring more accurate screening for all cancers and life changing, preventive treatments so the common cancers no longer require the invasive, disfiguring and often life altering treatments currently available.