As many people here write, with Latex, most of the technical issues are already resolved. A few other technical issues might arise due to Latex, but they are usually easy to deal with.
However, what remains are rules on page limit, number of words or similar restrictions. And in most cases, you try to fit as much content as possible into the template. So when changing the template, you either have more or less space, so either you would want to add more content, or you need to remove content. Even with the same number of pages and other things being similar as well, due do small differences in the template, it will not match up. That is what takes effort.
But for the aspect on space restrictions, I have heard actually the opposite argument: By having this limitation, you save the reading time of all your peers. Often, the work you did can actually be compressed into such short format. You might need to leave out some details (if you publish the source code and make it reproducible, people could anyway check for all details though, so not really a problem), but you can focus on the actual important part. So, by wasting some extra time and effort of the author, you save a lot of time and effort for all readers by having this restriction.
If your work really does not fit the space limitations, maybe a different conference or journal would anyway be the better fit.
However, what remains are rules on page limit, number of words or similar restrictions. And in most cases, you try to fit as much content as possible into the template. So when changing the template, you either have more or less space, so either you would want to add more content, or you need to remove content. Even with the same number of pages and other things being similar as well, due do small differences in the template, it will not match up. That is what takes effort.
But for the aspect on space restrictions, I have heard actually the opposite argument: By having this limitation, you save the reading time of all your peers. Often, the work you did can actually be compressed into such short format. You might need to leave out some details (if you publish the source code and make it reproducible, people could anyway check for all details though, so not really a problem), but you can focus on the actual important part. So, by wasting some extra time and effort of the author, you save a lot of time and effort for all readers by having this restriction.
If your work really does not fit the space limitations, maybe a different conference or journal would anyway be the better fit.