I’ve never checked the box and rarely (if ever) mentioned it during interviews. That being said, if I were applying to work at Tandem or a JDRF-endorsed internship, my approach might change. 
There have only been two instances over many years when D has had a significant impact on my work life. The first was when I worked overnights in a hotel and had a bad low… I called my supervisor, who was very understanding. He not only covered for me but his wife took me to the ER to make sure I was safe.
The other instance was when I was hired as an overnight support manager for a company whose name starts with “Wal” and ends with a word that rhymes with fart. It turned out I spent about 80% of my time unloading freight trucks, which was not part of the job description. For the most part I did fine and self-managed with juice. After I figured out what the job really was, I informed my supervisors and all I asked was that they prompt me with “are you OK?” if I was ever acting strangely.
One day I had a bad low in one of the back stock rooms and was laying on the floor. After some time I got myself moving and got some juice, then went about my business. That morning I was called into the office and informed that my supervisors watched me on camera laying on the floor for over an hour. They gave me a speech about how they need to be able to count on me, how I should think long and hard about this job and how they have other diabetics with no issues.
As it turns out, my fellow D’s weren’t unloading freight trucks for ten hours a night. They were all cashiers.
Needless to say, I quit shortly after to take a contractor job elsewhere with crappy benefits. In my letter of resignation I alluded to how “reasonable” an accommodation it was to request my supervisors prompt me when something seems off. That phrasing really upset the store manager. 
Sorry for rambling! P.S., this incident and their behavior prompted me to NEVER shop at the chain in question again.