Most if not all modelling techniques are relevant to all scales, you just need a bigger baseboard or soldering iron to achieve these aims. Many times we have been told that 3mm is an ideal scale-it is- but the next statement is-'A pity no one makes it anymore' or 'Is there any ready to run?' Most are amazed by the amount of products available, I usually carry a file with lists of whats on offer. Plus there is an area group not too far away whose advice and help is freely given.
Thats why I and my fellow 3millers do it! Incorporated within 3mm is a multitude of gauges but we all have a common interest-3mm :ft.
I adopted 3mm because I grew tired of building 4mm layouts, with scratch built scenics, for the questions as to who made that loco, coach,wagon et al.
I get a satisfaction that it runs because I made it, its unique and I am modelling in the best scale.