With iOS 14, Apple has introduced new privacy features. When installing firebase through cocoapods, one of the options is to install Analytics without IDFA collection capability.
# pod ‘Firebase/AnalyticsWithoutAdIdSupport’
I would like to use that option but do not understand what the pitfalls or disadvantages of doing so would be down the line.
This feature helps attribute app installs to certain adds through the apple identifier they call IDFA (identifier for advertisers). It's immensely useful to measure effectiveness of ads not only for downloads and installs, but also for latter internal conversions in the app.
But it won't be used if a user doesn't opt in to be tracked starting from iOS 14. So the value of it is somewhat diminished, making the analysts working with an effectively bias-sampled data that won't extrapolate normally.
Anyhow, if you need to attribute the traffic you've purchased to the source/campaign you've bought it from, you'll need IDFA. Otherwise, you're perfectly fine using AnalyticsWithoutAdIdSupport.