When taking on a new marketing campaign, the first step is to determine what you're going to track as 'conversions'. You have to determine what your key performance indicators (KPIs) will be.
There are a lot of different metrics you can track as a conversion. The most common metrics to track as conversions are sales, leads (i.e. form submissions, calls, chat initiations). These are typically called your macro-conversions.
Every campaign should at the very least be tracking these macro-conversions.
There are other types of actions we can track as conversions, like time on page, scroll percentage, or visits to a certain page. These are what we call micro-conversions. Little actions that visitors have to take on their path to becoming a macro-conversion.
For some campaigns, generating a lead via form submission or call could also be considered a micro-conversion.
But let's not get too bogged down on these technicalities.
Let's get to the main question you're looking for an answer to...
Should you bother tracking micro-conversions in addition to macro-conversions?
Absolutely! When it comes to Google Ads I'll typically track the macro-conversions for the campaign 'in column' and I'll track both micro and macro conversions in Google Analytics. I don't like to mix them both 'in column' for Google Ads because they don't have the same value to the business.
Tracking micro-conversions can be extremely useful for campaigns that don't generate a lot of macro-conversion data. Campaigns that maybe have a high ticket product and/or longer sales cycle.
It allows you to get actionable data a lot faster which can help you to reduce wasted ad spend earlier in the campaign.