Link-Local addresses are required for the operation IPv6, but not for IPv4. Microsoft, among others, has developed the APIPA (Automatic Private IP Addressing) standard using IPv4 Link-Local addressing, but it is not mandatory or supported by all OSes. I also have seen people misuse IPv4 Link-Local addresses by manually assigning and subnetting them, and that is against RFC 3927, Dynamic Configuration of IPv4 Link-Local Addresses, which is a standard.
Please read RFC 3927, Dynamic Configuration of IPv4 Link-Local Addresses:
As the Internet Protocol continues to grow in popularity, it
becomes increasingly valuable to be able to use familiar IP tools
such as FTP not only for global communication, but for local
communication as well. For example, two people with laptop
computers supporting IEEE 802.11 Wireless LANs [802.11] may meet and wish to exchange files. It is desirable for these people to be able to use IP application
software without the inconvenience of having to manually configure
static IP addresses or set up a DHCP server [RFC2131].
This document describes a method by which a host may automatically
configure an interface with an IPv4 address in the 169.254/16 prefix
that is valid for Link-Local communication on that interface. This
is especially valuable in environments where no other configuration
mechanism is available. The IPv4 prefix 169.254/16 is registered
with the IANA for this purpose. Allocation of IPv6 Link-Local
addresses is described in "IPv6 Stateless Address Autoconfiguration"
Link-Local communication using IPv4 Link-Local addresses is only
suitable for communication with other devices connected to the same
physical (or logical) link. Link-Local communication using IPv4
Link-Local addresses is not suitable for communication with devices
not directly connected to the same physical (or logical) link.
Microsoft Windows 98 (and later) and Mac OS 8.5 (and later) already
support this capability. This document standardizes usage,
prescribing rules for how IPv4 Link-Local addresses are to be treated
by hosts and routers. In particular, it describes how routers are to
behave when receiving packets with IPv4 Link-Local addresses in the
source or destination address. With respect to hosts, it discusses
claiming and defending addresses, maintaining Link-Local and routable
IPv4 addresses on the same interface, and multi-homing issues.
When IPv6 was developed, many things were built into it that had been optional, add-on features of IPv4. Link-Local addressing was one of them. Every IPv6 interface is going to get a Link-Local address so that a device can at least communicate on the local link, and, as a built-in feature, many things, e.g. routing protocols, use it for communications on the local link.