Its actually MSI vs C2R.
Difference 1 -
With msi installer, you can select which product you want to install or skip by directly using setup, but with c2r you have to use a configuration file manually which tells which product it will install or skip.
Difference 2 -
c2r method contain all the version (i.e. pro, visio etc) in only one setup, where msi method only contain those version which are mentioned (i.e. proplus msi method won't contain visio)
Difference 3 -
c2r office can not be updated with windows update but it uses its own update method, but msi can be updated with windows update.
Difference 4 -
c2r installation is fast, msi's slow.
Difference 5 -
from 2013 to 2016 both have c2r and msi offices, c2r is by default is retail channel and msi by default is vl channel. and if you are using c2r then to activate it with kms you first have to convert it to vl only after that you can activate it.
but with msi offices are vl by default so you can directly activate it with kms,
but since office 2019 this trend is changed,
now there is no msi, only c2r
so there will be c2r with vl by default.
and with configuration file you can can install 2019 c2r as retail or vl as you want, or just install it then later convert it.
i hope its clear for you now.
