Similar kits are available elsewhere for less money, although the quality of the plastic openers* varies.
I have stripped down and performed major surgery on phones a few times; and so far all have worked afterwards; however I wouldnt go opening anything for "fun"; only if the alternative is throwing it away, or when paying someone else would cost more than the device is worth.
*A set of various thickness guitar plectrums would do the same job, and for a lot less.
For computers, the need is even less, just about any task needed on a PC can be done with a No.2 Philips screwdriver, a broad flat head screwdriver (for levering), and a pair of long nose pliers.
If you want to do component level repairs, you need a lot more gear, and a lot more knowledge; I was trained down to component level, and these days I wouldnt touch a board unless it was already dead and I had nothing to lose.
Of course, in my young and foolish youth, I used to unsolder RAM chips from motherboards and replace with upgraded parts !! And do cut track mods to increase VRAM availability!!! (Back when the Amiga was king).
If you want to get down to this level, I recommend a large stand mounted magnifying glass with integral spot light, and a solder station with extractor fan to avoid toxic fumes.