Riding, you simply don’t know they are there. It’s the same bike, same frame, additional weight is marginal. We did have a phase of one starting to loosen a bit when riding, but probably just cos I’d not torqued it up enough (this was a tandem MTB so perhaps a bit more flex going through the frame than most applications). Anyway that hasn’t happened in a few years now.
As for packing and unpacking, it’s not a particularly easy or efficient process IME. I doubt it would be a good choice for a regular bike/train commute, for example. It’s a big bulky heavy object even when packed into a hard case (which weighs about 7kg in itself). Ours gets used mostly for decent length holidays, usually flights but sometimes train where a full-sized tandem often just won’t fit. On the train we’ve got away with just splitting the frame in two and strapping both parts together.
Depending on how you travel and how fussy you are about the bike, a proper folder might be a better choice.