The method, dubbed as Magecart, has developed in popularity amongst attackers for its combination of relative effectiveness and simplicity. They do not have to do much more than add nasty scripts (directed to distant servers for command & control) and wait for users to go shopping. From here, they can employ the data to make fraudulent buyouts, sell the info on the black market, and make clone cards.
Do not hope for these types of hacks to subside soon any time. They have been employed in opposition to various major brands, comprising Newegg, British Airways, and Ticketmaster. Until online shops are airtight in opposition to methods such as Magecart, they will be tempting targets.
On a related note, a number of bad actors will not get close to web browsers outside exploiting their errors, but a group is making improvements. Kaspersky has stated about efforts by Russian group Turla to fingerprint TLS-encoded web traffic by altering Firefox as well as Chrome. The team infects systems first with a distant access trojan and utilizes that to change the browsers, beginning with setting up their own certificates and then changing the creation of pseudo-random number that settles TLS connections.