Sounds like if you compile the application as a single unit you don't need
the DLL as it is only used by the compiled application you make. If on the
other hand you have various sub-applications or are making a suite of
programs based on Qt you will need to have a Qt library (DLL/libqt)
available to any program that need it in Windows. If you expect to wite
more then one program go with the libraries, if you are only making a
single application use the static one.
Libraries are commonly accessible collections of popular data and program
modules usable by many different programs, such things as internet
connection protocols, Quicktime Player or Flash routines are libraries,
they may not linked to any one program (and usually any program could use
them). So to keep programmers from installing six similar flash players,
the library provides the functionality for any programs that need it.
In order to run Python on a system you need a python language library,
either static (installed and used only by the program you wrote) or dynamic
(installed in a common place and usabile by your python app and any other
Python app they choose to install).
Larry