Agreed - I'm not sure why we assume that a modern smartphone is designed to be completely taken apart and reassembled with a standard toolkit.
I've had two third party repairs on my iPhones - one was done with a heat-gun and the finish was awful and the screen popped up in one corner at the end and the metal frame was dented from the pry-tool, and the second shop used a proper heat pad and an assembly tool and the finish was like it was a new phone.
Personally I would have been suprised if Apple recommended/advised use of a hairdryer / conventional heat-gun when that's not what they use themselves and clearly not how the iPhones are designed to be reassembled. Also presumably asking amateurs to use a heat-gun on their electronics would come with it's own risks (particularly heat guns + lithium batteries if you aren't careful!).
Like this article includes the following complaint:
> The repair manual not only suggests you need three pages worth of tools but also a jar of sand in case your battery catches fire — one of many not strictly necessary items that don’t come with the kit.
This doesn't sound entirely unreasonable from Apple's perspective - because at their scale they probably should be worried about the risk of people piercing the battery during a repair or using a heatgun near their battery. Also seems weird to throw shade at Apple for sending you too much stuff, but then also note that Apple didn't ship you a bucket of sand, but appreciate that was a kind-of joke.