I'll admit first off I've only ever glanced at BL stuff, never actually properly read it, so my opinion is going to be fairly ignorant but it's important I think to hear from someone 'outside' of the webcomics bubble.
First, I think it's great for marketing, to be able to say you have a dedicated space for these types of comics. It signals to creators and readers who come across the site that this is a site where all perspectives are welcomed and given somewhere to exist.
Secondly, it's my impression that BL is, even without this new addition, its own genre already. It looks to me to have its own tropes and idiosyncrasies. Most importantly, it looks to me to have its own specific audience.
The Romance genre also has its own specific traits, and from what I've seen, the two are not perfectly aligned, and indeed, they diverge greatly in some respects.
That's not intended as a moral judgement on whether or not BL is or can be about small r romance, of course it can, so can fantasy, and sci-fi, and slice of life etc, but I think anyone would be hard pressed to find something incorrect about the statement that all BL stories are romance stories, but not all romance stories are BL stories.
I also don't think that just by having two gay men in your romance story, it automatically becomes what the average BL fan expects from a BL story. You see this quite often now in many mainstream TV shows, where some characters are gay, and it's not anything special, or interesting enough to make a point about it, or even mention it. It's just another character trait that's established which often has very little to do with the greater story. Such shows are not considered gay shows, not in the same vein as other shows which are trying to tell uniquely gay stories.