Simple things, or even complex prototypes, get created in office apps because the office apps are their, have the flexibility, and you don't need to get IT to install something new (or allow you to), or convince finance to let you pay for something new, or convince compliance/security/other than the something new is safe anyway, etc. Also in a larger company, once the discussion of developing or buying something comes up lots of other potential stakeholders might raise their heads above the parapet and want to get involved (“Could our dept use this too?”, “We would need it to do Y as well as X…”, “That sounds useful, but it should be
us doing it instead”, etc.), and suddenly the quick PoC that has been barely started has become a series of interminable meetings.
The loophole is that if you have Office or similar you have a variety of development environment, IT/compliance/finance aren't caring what files you produce with the applications you have, and no one else is paying attention initially either, but would have a say (and a procedure for you to follow) if you wanted to bring in or create a new application. The usual process is bypassed.
This is more commonly associated with Excel, but it applies to Access too (less so than it used to, but there are still plenty people out there who rely on it daily).
Once the demo/prototype/PoC is there it is a lot easier to “fix up” that than spin up a project in anything else, or get something else in that is already available, for the same reasons as why it was done in Excel/Access in the first place plus the added momentum: the job is already at least part way done, using something else would be a more complete restart so you need to justify that time as well as any other costs and risks.
[Note: other office suites exist and have spreadsheets & simple DBs with similar capabilities, or at least a useful subset of them, of course, but MS Office's Excel & Access are, for better or worse, fairly ubiquitous]