If the LAN port of a wireless access point is 100 Mbps, then what is the need of 150 Mbps wireless speed? Why do they give 150 Mbps wireless speed?
Virtually all professional WAPs (what are on topic on this site) have 1 Gbps ethernet ports.
A WAP is a translating bridge, it translates from ethernet to Wi-Fi and back. You need to understand that you have two different, independently-developed technologies being bridged. One technology, ethernet, has standards for different speeds (10 Mbps, 100 Mbps, 1000 Mbps, and 10,000 Mbps) on UTP. Each bump in speed costs more, and it took some years between bumps in speed. On the other hand, Wi-Fi was developed for its medium (radio), and it has multiple standards, each with its own maximum theoretical speed. Because of real-world obstacles, it is unlikely that you can get anywhere near the theoretical maximum speed on a WAP. To bridge these disparate technologies, you need to use what each technology offers and balance the price/performance ratio, otherwise your product won't sell.
Wireless connectivity is a half-duplex medium. So while a single PC connected wirelessly at 150Mbps to the AP that is connected to the LAN at 100Mbps seems silly, the idea is that many PCs or hosts will be connected to the AP, sharing that 150Mbps half-duplex connection. The 100Mbps wired connection is probably full-duplex, so you are still getting better throughput on the wired side even if it is listed as 2/3rds the speed.
As an aside to KorXo's port-channel answer, port-channeling is a redundancy mechanism, not a speed improvement mechanism. The hashing algorithm of a port-channel typically only sends data down one of the links, not both. Even the best hashing algorithm (in my opinion) of src-dest-ip mixed with src-dest-port will only send each TCP/UDP connection down the same one link. Now a new connection to the same server will use a different source port, so might use the 2nd link, but you are still only using a 1Gb link for each connection. You get no better throughput because of that.