I think the biggest reason why maps were charming, at least to me, stems to the bedroom map itself. When I was younger and still had ample Legos to play with I would create this entire world within my own bedroom - my bed would function as a vast cave underneath the sheets, my desk would work perfectly as a city as it was a flat surface I could build things on, the entire floor was typically a desert or an ocean, etc. - and sometimes I would extend this world I've made outside in my backyard, which would function as a large scale forest or jungle. And what's better than creating a world and playing it with friends? Of course, playing with Lego minifigs and such has huge limits, like everytime I would try and make my character swing his sword his hand would fall off and I would have to pick it up and stick it back on and such, and furthermore like my friends would leave Legos like everywhere so that wasn't fun, picking up all those tiny Legos out of trees and underneath the bed.
Before I found Blockland, I played Roblox, but I don't think it quite captured my heart as I thought it did, rather, when I played the demo of Blockland I was ecstatic. I could actually PLAY as my character without his arm falling off, in a bedroom, albeit without a desk, with a vast outdoors to expand to; I could create this world and share it with friends much easier than I could in real life, but still have that feeling that I did when I was 5. I think what Bedroom really did was create this kind of nostalgia and that really hooked me into Blockland. Zoom like 6 or 7 years later and now shaders has been around for a while and I have yet to enjoy a single fruit of its labor since I've had somewhat lower end computers ever since. Not to say I don't think the game is fun anymore, I really enjoy these new builds that have been emerging which go hand in hand with a lot more effort, and I applaud everyone who's able to do these well, models as of late have been really killer the past few years, and environments really help in making those builds become more immersive as, instead of having to change to like a rainy map or like skylands you could just do it without reloading, I just feel like that kind of childhood nostalgia that I once had has faded ever so slightly.