Understanding the Limitations of Lightning Web Components | Salesforce Lightning

Before starting the discussion about the limitations of LWC, Let’s discuss the supported features of Lightning Web Components:

• Lightning Experience: In present-time UI enhanced for speed and responsive plan for all the devices.
• Salesforce Mobile SDK: It empowers developers to construct custom mobile applications custom-made to their particular business and UI needs.
• Custom Tab: You can easily add a custom tab by adding lightning__Tab ( it targets the component’s configuration file) in <component>.js-meta.xml (It describes the metadata values for the component).
• EMP API: The lightning/empApi module gives admittance to techniques for subscribing to a streaming channel and tunes in to the event message. All streaming channels are upheld, including channels for platform events, generic events, PushTopic events, and Change Data Capture events. It needs API version 44.0 or later. This is the syntax of the import method:
  import { subscribe, unsubscribe, onError, setDebugFlag, isEmpEnabled } from 'lightning/empApi';

Don't forget to check out: How to Host LWC OSS Apps on Github Pages | Salesforce Developer Guide

• Changesets: You can deploy your lightning web component using changesets like the other aura components.
• Unlocked Packages: It assists you with adding, removing, and eliminating metadata in your organization in an identifiable way. You can install unlocked packages to various organizations, and overhaul your Salesforce applications simpler and quicker.
• Lightning Out: If you need to run a Lightning Component outside of Salesforce on your own server,  yet the information is in Salesforce then you will need to utilize Lightning Out.
• Experience Builder sites: This is the Syntax of the import method:
  import propertyName from '@ salesforce/community/property';
  If we add this imports (@ salesforce/community) method, It means it will only target the Experience Builder Page and you can not use this in other SF containers.
• Gmail and Outlook integration: If you want to create an LWC component for the Gmail and outlook integration you have to add the lightning__Inbox (this target define the three properties: subject, messagebody, and people that’s used in the template) as a target and update <isExposed> false to true in the lwc component’s configuration file. 
• Embedded Service Chat: It includes these target tools: Base Chat Header, Base Chat Message, Base Pre-Chat, and Minimized.

Target Tools

Base Chat Header: syntax of import method is ‘ import BaseChatHeader from 'lightningsnapin/baseChatHeader'; ‘

Base Chat Message:  syntax of import method is ‘ import BaseChatMessage from 'lightningsnapin/baseChatMessage'; ‘

Base Pre-Chat: the syntax of the import method is ‘ import BasePrechat from 'lightningsnapin/basePrechat';’

Minimized: the syntax of the import method is:
‘  import { assignHandler, maximize } from 'lightningsnapin/minimized'; ‘

Check out another amazing blog by Shweta here: Learn All About How to Use Lightning Spinner | Salesforce Lightning Component

Limitations of Lightning Web Components

Here is the list of features that do not support Lightning Web Components. If you want to use these features you have to switch to the aura components.

• Quick Action API
• Custom Actions
• Global Actions
• Related List View Actions
• Chatter Extensions
• Omni Toolkit API
• Salesforce Console APIs don't support Lightning web components. And these are the Salesforce console APIs: Navigation Item API, Workspace API, Utility Bar API
• URL Addressable Tabs
• You can not use email templates in the LWC component.

You can not create lightning web components in the c. If you want to create lightning web components, You have to use visual studio code, and also you will need CLI extensions for SalesforceDX.