Just a minor precautionary note I think is worth adding:-
The browser market share statistics take into account all the millions of PCs in the corporate world and internet usage from large population regions (like India and China). Both these factors add a sizeable “skew” to the browser market statistics (think lots of old computers and state-owned web browsers like Baiidu and Yandex that masquerade as Chrome). Naturally there are many people in these demographics who may not necessarily ever come to the sorts of websites we build.
As a prime example, a popular web browser statistics website is quoting today that Firefox only has a 5.5% market share. It is also claiming that Mac OS X users only makeup 3.5% of total visits to websites.
I am certain that if you are collecting your own analytics and drill-down into the browser statistics, the usage of Firefox and operating systems like Mac OS X would be a lot higher. Possibly closer towards a quarter or a third of all the traffic you are getting.
No one is right or wrong! You see, the trouble is that there isn’t really any definitive browser market share statistics available that are truly reliable. A lot depends on the type of website you are building and your target audience.
Unfortunately “Facebook” and “privacy” don’t really go hand in hand together! Data is a prized commodity (equivalent to oil and gold in previous centuries) that big businesses crave.
Firefox and Brave web browsers both have similar “container” functions, to protect user privacy. There are other web browsers and extensions that do the same. Laws like GDPR, DSVGO, APEC-CBPR and CCPA mean that website users now need the right to opt-out of potentially harmful tracking.
Even a simple ‘like’ button can pull several megabytes of scripting from a third party website. This virtual ‘window’ can give social media platforms free roaming access to monitor all your website users and collect data - which they can resell. Scary stuff, when you think about it. For this reason, Firefox and other more ethical web browser providers are adding options to block invasive tracking.