The argument that some have made that it looks ridiculous to wear a jacket with tefillin is in fact a ridiculous argument.
You wouldn’t wear tefillin in front of the president; that would look ridiculous. That doesn’t stop us from wearing it in front of Hashem; in that context it is beautiful and elegant.
The normal way to wear a jacket when wearing tefillin is to have one arm out; there is nothing ridiculous about it.