Acknowledging all of your points, Mariners, here’s a good, every-day example of a distinction that I might draw:   “given the requirement to ‘store large images,’ do you store those images in your RDBMS, or do you instead store filenames?”

There’s no bright-line rule.   It depends on many things, including how well your particular database implementation handles “large BLOBs.”   Also to be considered is the fact that any file-system is also “a database of sorts,” which is extremely adept at storing variable-sized objects using a single key otherwise known as a “file name.”   Both approaches are defensible and we have all seen both of them done.

If the files which contain the data are enormous, and/or if they are already being used for other purposes by other existing applications, then it might well not be appropriate to move these data into an RDBMS, but, instead, to use the RDBMS as an index.   There is still a lot of high-volume data processing which requires the use of sorted files, with sorted updates being applied to those always-sorted remains-sorted files, specifically to avoid random-access.   But an RDBMS might still be useful for quickly and directly finding the location (exact, or approximate) of whatever data is being sought, thereby allowing the records to be queried randomly.   It is an admitted compromise, to be judiciously employed if and when the case arises.