Psychedelics can be fun, but in my experience they're fun if your mind is in the right place. They act as a conduit for more deeply connecting with the world around you.
On the other hand, if you have work to do then those things have a chance to appear in your trip. That can be healthy, if you're ready to face something, or it can be incredibly terrifying. I've had both experiences through my own isolation and meditation before. As someone with years of trauma, including a year long stint in a war zone, I can attest that my trips were sometimes fun, almost always challenging, and sometimes terrifying. As time has gone on and I've done work to unpack my trips and connect them with my experiences and understanding when I'm sober my trips have averaged to being "more fun" and "connected". This is something I was not able to achieve with meditation alone.
Yes, and there's no guarantee that your bad trip or encounter with these entities will resolve itself without major effort. That ought to be enough to be seriously concerned about whether it is in any way appropriate to endorse this as some sort of ordinary, routine practice for the uninitiated.
I don't think most users of psychedelics view them as a "tool" for serious spiritual practice. They just think tripping is a lot of fun.