Ulysses definetely has that option in its settings
That is an unexpected answer 
Generally i would say: why not! There are several issues with markdown standard, f.e. that tables are forced to start with a header or my issue with quotes.
If it makes sense it should be considered imo. But there must be a criterion NOT to break standards even if it would make sense, namely then things would break in terms of interoperabilty. I do not know how other editors are working in regard to code blocks written by ident, but let’s say bear would not interpret such an imported note anymore as codeblock due to its non-standard handling THEN the adoption to standard should be kept. Vice versa also it should be considered how other editors would interpret exported notes from bear. If there would not be a conflict i see no reason to adopt to standard as long as there is a real benefit to break (a little bit) the standard.