Playing conkers at 23 years of age is a bit wrong. It is a bit like building LEGO kits as an adult, particularly wrong if the goal is to just build the design on the box and put the completed model on a shelf, rather than build your own creative masterpiece.
Please resist the urge to mod me down in flames for the above, but, in former times, buying LEGO at the ripe old age of fourteen would be a bit shameful in the school playground. Adults did not play LEGO then, it was the role of the father to read the newspaper and the role of the mother to be 'chained to the sink' in those days, with LEGO just for small children.
Conkers was very much for younger children, once an interest in the opposite sex, playing cards for match sticks or general juvenile delinquency was established, conkers was 'grown out of'.
Much like how fathers could teach their sons to beat up bullies, so it was that fathers could help with the technical aspects of conkers, such as getting the hand drill out (remember those contraptions, before battery power tools).
Conkers was a rite of passage, something that you would be expected to grow out of. It also came with a season, i.e. autumn, and the etiquette was to pick on someone of your own size. Hence, someone playing conkers at the age of 23 has not really got it right.
As for the guy with the steel conker, again we have a problem of age.
Now, as for playing with LEGO as an adult, or playing conkers as an adult, or, for that matter, the retro 8-bit computer scene, this is about regressing from the adult world of today, with all of its problems, and hiding in a recreated childhood. This is sort of understandable for people that were sent off to war, to see things they did not need to see. Those people kind of need the therapy that a return to the child world provides.
But nowadays, I see it as a response to the atomisation of community. If you are not spending your weekends with friends at pubs or at dinner parties, if you don't have an adult hobby such as with a lathe in a shed, if you can't afford big toys such as a boat, then childhood hobbies are a safe space to return to. Apart from anything else, you can buy all the LEGO that you could not buy then. Or, with conkers, you can find a social scene of like minded individuals and get a bit more scientific about winning.