Choosing an off-the-shelf commercial antenna for your connected product can solve many problems ! But only if your product operating constraints allow you to comply with the recommended integration requirements, which is often not the case !, and not following them, can unfortunately lead to questioning about the usefulness of the antenna !
In many cases, integrating an off-the-shelf antenna is quite possible. However, to guarantee at least an acceptable antenna efficiency, this must not be done without precautions and verification measurements, in both, conducted and radiated way, in order to ensure the correct antenna integration regarding your operating and product constraints.
This can be achieved through:
Selecting the right type of antenna technology (ceramic, wired, PIFA, etc.)
Making the right choices regarding the mechanical design of the product…
Optimaizing the placement of the various components of the product, in particular that of the antenna
Adding matching components to your PCB if needed, to tune the antenna to the useful frequency band
Selecting the right coating material (RF characteristics..etc.), when applicable...
...and many other techniques, depending on the nature of the constraints encountered.