  We accurately identify and classify the variability of A-F stars in the
southern continuous viewing zone of the TESS satellite. The brightness limit
was set to 10 mag to ensure the utmost reliability of our results and allow for
spectroscopic follow-up observations using small telescopes. We aim to compare
our findings with existing catalogues of variable stars. The light curves from
TESS and their Fourier transform were used to manually classify stars in our
sample. Cross-matching with other catalogues was performed to identify
contaminants and false positives. We have identified 1171 variable stars (51 %
of the sample). Among these variable stars, 67 % have clear classifications,
which includes $\delta$ Sct and $\gamma$ Dor pulsating stars and their hybrids,
rotationally variables, and eclipsing binaries. We have provided examples of
the typical representatives of variable stars and discussed the ambiguous
cases. We found 20 pairs of stars with the same frequencies and identified the
correct source of the variations. Additionally, we found that the variations in
12 other stars are caused by the contamination with the light of faint nearby
large-amplitude variable stars. To compare our sample with other variable star
catalogues, we have defined two parameters reflecting the agreement in
identification of variable stars and their classification. This comparison
reveals intriguing disagreements in classification ranging from 52 % to 100 %.
However, if we assume that stars without specific types are only marked as
variable, then the agreement is relatively good, ranging from 57 % to 85 %
(disagreement 15-43 %). We have demonstrated that the TESS classification is
superior to the classification based on other photometric surveys. The
classification of stellar variability is complex and requires careful
consideration. Caution should be exercised when using catalogue
classifications.
