Is it True that Category 7/8 LAN Cables Are Not for Home Use?

Yes, it's true. The reason lies in the "standards."

The category (Cat) designation follows the American standard "ANSI/TIA-568," and to meet the specifications for Cat.7 and above, special connectors are required, which are not intended for general home use.

In other words, while there are products both domestically and internationally sold in LAN cable sections that can be directly plugged into home WiFi routers and are labeled as "Category 7" or "Cat.8," none of these are made according to official standards.

"Category (Cat.)" represents the cable specifications, and roughly speaking, the higher the number, the faster the communication speed it supports.

As speeds increase, cables with appropriate noise countermeasures are manufactured according to the aforementioned standards.

Therefore, for general home use, "Cat.6A" is currently the most recommended option. Cat.6A supports 10Gbps and can deliver the highest class of communication speed for home use. Using Cat.7 or higher for home applications would not provide value for the price.

1 Category Table
2 What is TERA?
3 [Summary] For General Home Use, "6A" is Recommended

Category Table

The categorization is based on the American standard "ANSI/TIA-568."

	Maximum Speed	Frequency Characteristics	Ethernet	Connector
Cat.8	40Gbps	2GHz	25G/40GBASE-T	TERA, GG45
Cat.7	10Gbps	600MHz	10GBASE-T	TERA, GG45
Cat.6A	10Gbps	500MHz	10GBASE-T	RJ45
Cat.6	1Gbps (up to 10Gbps within 55m)	250MHz	1000BASE-T, 1000BASE-TX, (10GBASE-T for short distances)	RJ45
Cat.5e	1Gbps	100MHz	1000BASE-T	RJ45
Cat.5	100Mbps	100MHz	100BASE-T	RJ45

In addition to TIA, there are similar standards such as ISO/IEC 11801, and JIS X5150, which is the Japanese translation and JIS standardization of it. This page explains the TIA standards that are generally more familiar.

What is TERA?

Except for special cases involving network-related work, the LAN connectors you usually see are called "RJ45." RJ45 is used in most WiFi routers and network hubs sold at electronics stores and is widely adopted.
On the other hand, the connectors specified in the Cat.7 standard are mysterious connectors called TERA, GG45, ARJ45, etc. For example, TERA looks like this: