Yes, I've come across a few of those fillable PDF files that can't be saved. Thankfully none were documents that I needed to use more than once or twice. Incredibly annoying.
When I politely suggested to HR that we might want to consider one of the various digital signature solutions the response I got was bizarre. HR person thanked me and then said she would talk to IT about it. I read that and was like WTF? It would be up to you, as the HR director, to decide that digital signatures are acceptable for the various HR related documents we have to do, and then IT would only have to make sure that everyone who needs to sign those docs has a license for the software. Based on the response I assume that our HR department will be moving into the 2010s sometime after my work-o-meter has expired 7-8 years from now. Unless I toss this idea out to the CEO the next time I talk to him...