Gone are the days when you can build an app and give no thought to mobile.
Since most usage today is on a tablet or a phone, every application is going to need to take this into consideration.
The question is not whether or not your users will access on a mobile device; the question is which mobile device will they use and what kind of user experience will they have on it?
One of the popular ways of building out a FileMaker business app is to build out hybrid layouts which look and work great on mobile but also function great on desktop. These give the user a great mobile experience and they also give the desktop user a very good experience. The only downside is that because you are using the same layouts for desktop and mobile, in some cases the layouts will be smaller than the full-sized desktop screen. But in many cases, this can be compensated by making use of the object anchors of some fields so that they will stretch out to a larger size for the desktop user. These have to be carefully tested, however, as you can get overlapping objects if you are not careful.
There is, of course, the issue of total screen real estate. You simply cannot fit as many objects onto an iPad-sized layout as you could put on a desktop. But this can be a good thing, as it forces you to decide what is most important. Also, with the use of tabs and sliders, many of the issues with less screen real estate can be handled. Making the decision about what are the most important elements which the user can see is a good exercise in building a quality user experience.
And of course, if you are going to make use of a phone-sized layout, these considerations are amplified.
We recently made a very beautiful phone-sized layout for the National Association for the Protection of Children. They were using the State of MN and its crime statistics for a national study. You can see the results here. (For best results, open it on your phone!)
So as you give consideration to your next FileMaker business app, be sure to include the mobile layouts into consideration.