You can't be approved with one based on the CRLs, but don't let that stop you from having one for non-canon events, which are most of the trooping events. Just use loops like the TK ESB holsters, so you can easily put it on or off.
As for PO or SWAT, people do it for all different reasons. Some for the challenge, others for status and being able to purchase PO/SWAT specific merchandise, and others may just want a super accurate Sandtrooper. It is just a personal choice if you want to go for PO or SWAT.