Of course it is. But preterminated fibre from eBay is so cheap that cost is not a reason to avoid doing it. However, fibre does give one real advantage over copper cable for long runs. Total immunity to propagating lightning. The mains cabling is still there of course, but there have been many instances of network cables spreading lighning damage around.
required them even OM3 will be outdated.
Maybe. Pre-terminated 9um single mode fibre cables (OS1) are just as cheap. Its hard to see how they could get outdated in the forseeable future. They will usually (every time I have tried it) work perfectly well with cheap 850nm multi-mode transceivers, most of which use vcsel diodes which put a lot of light into a single mode fibre, even though this is not what they were designed for.
Yes, totally OTT, but very easy and very cheap to do:-)
Another slightly more serious thought though. Fibre with its first layer of plastic cladding but that has not been incorporated into a robust cable is slightly less than 1mm thick, so several fibres could be run up the corner of a wall and wallpapered over without leaving a discernable bump. This might be useful in a listed building or similar situation. Such fibre could also be run through conduits containing mains wiring - as could duplex fibre cables without connectors. Terminating them is a bit fiddly, but kits do exist that need minimal equipment.
John