I kinda feel the same about these two games as well but Hades is my favorite roguelike, my 2020 GOTY, one of my favorite games on Switch and a top 3 indie game for me
The biggest difference I would say is how defined the gameplay loop is. Bastion is a pretty game and was pretty hyped back then, it apparently had Zelda and Diablo inspirations but it doesn’t scratch either of those itches at all, it’s a pretty straightforward action game. Transistor is the same, it’s even prettier and more unique but besides battling you don’t have much agency throughout the game, like you get lore dumps for reading the terminals and unlocking the character backstories by using their abilities but that’s it. Hades has a much stronger hook than either of those games. First off the roguelike structure obviously spices things up. It’s a faster paced game as well so you feel much more powerful in action. Now the thing is that Hades actually encourages you to try different builds, you get to choose with which god you get to max your relationship level with first. This gives you a level of agency that isn’t really present in their previous games. Speaking of builds, the game has great balance, no runs feel dead since you always can make the most of what you get. I feel like a problem with a lot of roguelikes is when they have huge difficulty spikes, or when they are way too rng dependent so unless you get the right loot and synergy the game simply isn’t fun. Hades is one of the rare roguelikes that don’t fall into this trap at all (the only other ones I played so far that do this well are Slay the Spire and I guess Vampire Survivors). It’s definitely a no brainer, even if you end up not playing it until you get the true ending you’re still looking at a solid 15-20 hour action game for half price at worst, go for it tbh