In my career I found several reasons not to use regular expressions for parsing an HTML response, but the largest was the fact that it may work for 'properly formed' documents, but you would be surprised how lax all browsers are about requiring the document to be well-formed. Your regex, unless particularly handled, will not be able to handle sites like this (and there are a lot, at least from my career experience). And you may be able to work 'edge cases' into your RegEx, but good luck finding anyone but the expression author who fully understands and can confidently change it as time goes on. It is also a PITA to debug when groupings/etc. aren't working (and there will be a LOT of these cases with HTML/XML documents).
It is honestly almost never worth it unless you have constraints on what packages you can use and you MUST use regular expressions. Just do your future-self a favor and use BeautifulSoup or some other package designed to parse the tree-like structure of these documents.
One way it can be used appropriately is just finding a pattern in the document- without caring where it is w.r.t. the rest of the document. But even then, do you really want to match: <!-- <div> --> ?
It is honestly almost never worth it unless you have constraints on what packages you can use and you MUST use regular expressions. Just do your future-self a favor and use BeautifulSoup or some other package designed to parse the tree-like structure of these documents.
One way it can be used appropriately is just finding a pattern in the document- without caring where it is w.r.t. the rest of the document. But even then, do you really want to match: <!-- <div> --> ?