Ok, it seems that the information on Wikipedia was misleading. Here is what it said:
"Influenza spreads around the world in yearly outbreaks, resulting in about three to five million cases of severe illness and about 290,000 to 650,000 deaths."
300,000 deaths per 3 million cases would be a 10% fatality rate, but apparently that's only for severe cases. Further down the page it says:
[TABLE="class: wikitable"]
[TR]
[TH="bgcolor: #EAECF0, align: center"]Name[/TH]
[TH="bgcolor: #EAECF0, align: center"]Date[/TH]
[TH="bgcolor: #EAECF0, align: center"]Subtype[/TH]
[TH="bgcolor: #EAECF0, align: center"]People infected (est.)[/TH]
[TH="bgcolor: #EAECF0, align: center"]Deaths[/TH]
[TH="bgcolor: #EAECF0, align: center"]
Case fatality rate[/TH]
[TH="bgcolor: #EAECF0, align: center"]
Pandemic Severity Index[/TH]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
1889–90 flu pandemic[212][/TH]
[TD]1889–90[/TD]
[TD]Likely
H3N8 or
H2N2[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[TD]1 million[/TD]
[TD]0.15%[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
Spanish flu[213][/TH]
[TD]1918–20[/TD]
[TD]
H1N1[/TD]
[TD]33% (500 million)
[214][/TD]
[TD]20–100 million[/TD]
[TD]2–3%
[215][/TD]
[TD]5[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
Asian flu[/TH]
[TD]1957–58[/TD]
[TD]
H2N2[/TD]
[TD]8–33% (250 million – 1 billion
[216])[/TD]
[TD]1–1.5 million[/TD]
[TD]<0.2%
[217][/TD]
[TD]2[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
Hong Kong flu[/TH]
[TD]1968–69[/TD]
[TD]
H3N2[/TD]
[TD]7–28% (250 million – 1 billion
[218])[/TD]
[TD]0.75–1 million[/TD]
[TD]<0.2%
[219][/TD]
[TD]2[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
Russian flu[/TH]
[TD]1977–78[/TD]
[TD]
H1N1[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
2009 flu pandemic[220][221][/TH]
[TD]2009–10[/TD]
[TD]
H1N1/09[/TD]
[TD]10–200 million
[222][/TD]
[TD]105,700–395,600
[223][/TD]
[TD]0.03%
[224][/TD]
[TD="class: unknown table-unknown"]Unknown[/TD]
[/TR]
[TR]
[TH="bgcolor: #EAECF0, align: center"]
Seasonal flu[t 1][/TH]
[TD]Every year[/TD]
[TD]Mainly A/H3N2, A/H1N1, and
B[/TD]
[TD]5–15% (340 million – 1 billion)
[225][/TD]
[TD]290,000–650,000/year
[226][/TD]
[TD]<0.1%
[227][/TD]
[TD="class: table-na"]N/A[/TD]
[/TR]
[/TABLE]
So there can be up to 1 billion people infected by the seasonal flu each year. That's much more than I expected. The CDC report of 13 millions cases of flu this year also mislead me as I thought it was worldwide, but it was only for the USA (it was not mentioned anywhere on the page I linked above).
So the fatality rate is higher for Covid-19 than the seasonal flu, but the number of cases are incredibly low in comparison so far. The question is how long can the pandemic last before the virus mutates and loses strength? With the seasonal flu it's a few weeks or months. Can Covid-19 last for a whole year or more? That would be more worrying.