Conceptually, Zapier can be a hard thing to wrap your head around. The basic idea is that Zapier is the courier of data between applications. For example, if you have data in Google Sheets and you need to send it to Webflow... Zapier can act as the delivery mechanism between those two disparate applications. So even though Google Sheets and Webflow don't have a direct integration, both of them integrate with Zapier — which effectively brokers the data exchange between the two application.
There are thousands of applications that integrate with Zapier, which makes it a convenient way for tools to instantly integrate with a huge portion of web apps. In some ways, if a tool is not connect to Zapier it's data is on an island and inaccessible.
For Low Code workflows, Zapier is the go to resource for connecting applications. It connects to the most tools and has clean UI that makes complex "zaps" easy to build and manage. It does require an understanding of how data moves through your software stack, but it doesn't require any coding skills. There are other tools (more everyday) that solve similar problems and connect different corners of the web, but Zapier is the behemoth.
Unless we're dealing with unique use case that would be better suited for a different tool (Parabola, Integromat, etc), the majority of the time we start with Zapier.
Zapier is an invaluable tool for No Code / Low Code. It has democratized the connection and interoperability of web applications. Beyond just sending data from A to B, it also has really powerful features for adding logic, cleaning and formatting data, and a ton more. If you're building a low code workflow, there is a significant change you'll want to be utilizing Zapier.
My biggest qualm with Zapier is that my Zaps can just stop working. This is most likely not Zapiers fault, but more likely an issue with the tools API connection... but all of the error messages I see come from Zapier, so it feels like it's their problem. So while I love what Zapier enables me to do with my workflows, I am always anticipating the email notification that my Zap has stopped working and need my attention... which is frustrating.