But there are genuine wheelsize packing issues for the very small (kids and adults), on road and MTB, especially at the front end in terms of fitting a ‘big’ front wheel in front of the riders feet without having to deal with massive toe overlap or kinked geometry to accommodate it.
Same with getting bars at the right height when using big wheels (worse with bouncy forks), you end up with teeny tiny headtubes and massively negative angle stems.
I’m not saying you can’t make it all fit (look at Batty for example) but there are compromises that have to be made, sometimes they’re worth it for a particular benefit, and sometimes not, sometimes a smaller wheel is the better option if it gets round a load of other issues with fit or geo.
As always, it’s nice to have the choice, but it’s not so nice to have the choice dictated to you by someone else.