Nice, you are finally starting to put together a cost benefit analysis. I'll walk through a few of your points and provide a point or two.
The first point I can make is that I'm still inputting all the information into a digital format using a laptop computer. I only use the paper form to guide me though the logical inspection process moving point to point. That information is then typed into a laptop computer where it is edited for clarity along with the photos. Everything is available at any time and anywhere. The problem with the cell phone is that it makes entering information tedious and time consuming and puts the phone at risk for damage. A piece of paper and a clip board cost pennies over time. The cell phone program also promotes an inspector to just click the button instead of adding information that is pertinent.
Next item concerns specific inspection forms by machine. Most machines are engineered along a common theme. You have power supply, power transmission, actuators and attachments. It doesn't matter if it is construction, logging, mining or agricultural in use. The inspection path flow is generally the same for most every thing. Identification numbers, options and attachments, flies checks, engine, drive train, hydraulics, tires or undercarriage and finally operational checks. Once, what I call the dance steps are laid out in a logical progression, the inspector will basically have to ignore a check point to miss it. I use one paper inspection form which is set up as a template in my computer. What I put on paper is typed into the form in the same pathway as the inspection. One form covers all machines. Once the inspection is entered into the computer the forms can be thrown away. I keep a file box in the truck with about twenty or so blank inspection forms. Also in there are paper service reports, reference books for tires and undercarriage and it also is used for temporary storage for items I might need per job. I keep three clipboards, two always being used and one for a spare in case I run over one or the wind blows one into a canyon. The camera I carry allows me to take extreme close up photos which a cell phone camera won't focus on. In order to get that function at this time requires an add on lens that is another thing to carry and is small enough that it is easy to lose. I can also take photos in 640 x 480 resolution which is small enough to transfer quick but large enough to reveal any problems I'm trying to show. Really the difference between us is the manner that information is entered into software.
As far as standardization goes I see that as a management issue. Once a form is established why would someone be able to change it without management's approval. The bigger issue is who is going to write the form? Is it a knowledgeable mechanic / supervisor or is it something pulled from a manufacturer's recommended maintenance schedule? Maybe it is an owner who has experienced failures in the past and only wants certain items checked.
Analytics require communication of information across platforms. I assume you are using a spread sheet program for the process so it will require a lot of copy and paste or maybe a publish and subscribe function in order to format the information into a usable report. So far that requires a person to move the information cross platform and to have specific skill in what the information means and to interpret that into some kind of action. That doesn't change by using a paper form to accomplish an inspection and then typing it into a piece of software.
As far as immediate action goes, you will get more feed back from an operator's report long before a mechanic finds an issue. Maybe you should put the cell phone in the operator's hand instead of the mechanic's?
Your final point about experience I think reaches the heart of trying to impose this on your personnel. You are apparently assuming that your mechanics need something like this because you don't trust them to do the job properly. Maybe a little bit of training can do more to reduce expenses than exposing an expensive piece of hardware to potential damage and loss.
I think we have taken up enough space and time exploring this issue here. If you wish to continue this discussion I suggest we take it to messaging where we can exchange email addresses if you wish to go deeper.