A website contact form is easy to track. A phone call isn't, unless something is specifically set up to trace it. For a lot of home service and trade businesses, the phone is where most real leads actually come from, which makes call tracking worth the small setup effort it takes.
The basic idea
Call tracking assigns a unique, trackable phone number (or several) to different sources: one for the website, one for a Google Business Profile listing, one for a specific ad campaign. Calls to each number get logged and attributed to wherever that number was displayed, then usually forwarded to your real number automatically.
Dynamic number insertion for the website
A more advanced setup swaps in a different tracked number depending on how a visitor arrived at the site (from a specific ad, from organic search, from a direct visit), so the website itself always shows one number to the visitor while the analytics behind it separate the sources.
What it actually tells you
Which channel is producing calls, not just visits. A page can get plenty of traffic and very few conversions, or the reverse. Call tracking is often the piece that reveals a channel is working better than the visit count alone suggested, because visitors are calling instead of filling out a form.
It doesn't need to be complicated to be useful
Even a simple version, one dedicated number just for the website versus the number printed on a truck or a physical sign, answers the basic question of whether the site itself is generating calls at all.
Where it connects to a conversion
Once a call is being tracked, it can usually be logged as a conversion the same way a form submission is. See what is a conversion, and how do you track one on a simple website?
Questions
Does call tracking cost money?
Most call tracking services charge a small monthly fee per tracked number. For a business relying heavily on phone leads, the cost is usually easy to justify against the value of knowing what's actually working.
Will a tracked number confuse customers?
No, as long as it forwards seamlessly to the real business line. Customers calling a tracked number reach the business exactly the same way they would calling the number printed anywhere else.
Do I need call tracking if most of my leads come through a form?
It's more valuable the more your leads skew toward phone calls. A business that gets almost all its leads by form may get less value from it than one where the phone is the primary contact method.