Well I think it's important that Isaac is an engineer, his suit is also for that purpose not for fighting in the military.
As other people have already said, it works on its own, so in sudden dangerous situations, it can really come in handy, that you can rely on it, rather than you having to bother with it. Especially when necromorphs are running around everywhere - if you were talking with someone, holding your helmet, out of nowhere necromorph attack incoming, it could hit the helmet out of your hand, crush it, then crus your skull if your not fast enough.
So I think it's both practical and cool, I loved when I got a new suit and for the first time the new helmet equipped itself, you looked like you can now take on the next big thing coming.
Oh, and the argument that even if it's in the future, one part of the helmet would stop working eventually - I can only say that nothing is going to work forever, everything requires maintenance from time to time. In the game, they have giant planetcracking spaceships, and if humanity was able to create giant machines floating in space and ripping apart planets that are well QUITE F***ING BIG things - I think it's no surprise that such a helmet was put together.
Also considering you can get atleast four new suits progressing through the game, it means Isaac always has a new helmet every few hours, and if these things could just go wrong after using them brand new, folding it in 4-5 times between a couple of hours, I don't think it would be manufactured big time for engineers all around the universe.
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Sincerely
Inuprince
Spokesperson for Space-engineers Safety Gear Association (SESGA) - writing to you from Titan Station
Damn Necromorphs! We have no one to produce for anymore .... they took our job!!! ... and our bodies ... help ...