Well up to the Initiation of the Third Degree it is pretty reasonable and safe but that third initiation is the part that screws him over I believe and sets the tone for everything else that follows. This is where he Akasha-Subterfuge inside himself and submits to its will for its power and secrets but I feel the last thing you ever want to do is submit to a god of death of all things especially not one with a name such as that.
From my own experience I know most beings if you give them the chance to use you like that they will do so mercilessly and lead you on for as long as they can and once you give them a foothold they will not stop.
Past that point most of what is given can still be adapted and used but giving into these beings is just I feel not the way and opens yourself up to become as much a pawn and vessel to these beings as some fervent believers are just pawns and vessels to desert god in whatever name he is presented. Believe they are on the right path and acting of their own volition while doing their god’s will but ultimately end up being used for far less benefit than what they gave up.
This is not to say you should not communicate or work with such beings but you should do so in a reasonable manner. What Dante apparently did by account of the book is equivalent to I would say trusting someone who you only have a working relationship with, with the keys to your house and your full schedule for any given day of the week. It might not bite you in the ass but at the same time it is quite likely it will.
I find spirits especially the more powerful ones work by their own codes of conduct and are not inclined to play by any other rules so if you want to work with them you have to work your way up and play by the same rules. Approach them like two business owners might approach each other. Willing to work together for mutual gain but both likely looking for the opportunity to use the other.
Set clear exchanges for every meeting. For everything you gain something of equivalent value is given, no more, no less. Because while many might be willing to play fair others by their very nature are incapable of it and so you must study and learn to be like them without being shaped by them.
That is how I see it at least and I know it probably goes against what a lot of others believe here but I tend to take the more independent path to power relying less on those outside myself beyond learning from them and how they accomplish things. I don’t seek to have them grant me power only to study them and learn from them in equal exchanges so that I might take and grow the power I want myself.
I will be working through the book and adapting it to my particular way of doing things so I will post some updates relating to that when I start on it. The book is not flawed so much as it presents many lessons in what not to do. Those can be learned from and the knowledge that was gained through much suffering can be put to use in a safer more reliable way. Should never be seen as completely safe there is always risk but we should all strive to get the most out of what we have with as little risk as possible.