I can’t say this is true for every sort of game, but lot of games failure is part of the gameplay loop. If you can’t lose your progress, then there is no fear of losing a life, and therefore no tension is created. In example where this makes sense are Dark Souls and Resident Evil games. In Resident Evil you can only save if you find an object and consume it to safe… But also doing it like Stardew Valley to save only at specific points only means, its less work for the dev to figure out all possible details to safe and its more consistent with updates of the game, so it does not break the safe file. Even more so, if the game is multi platform. If the mobile version does save anytime, then it might use a different technology to do that. Not sure if it does and how it differs.

Just some thoughts about this subject. I personally find it totally normal and acceptable that games save on specific times only. In some cases not being able to save anytime is part of the gameplay experience and games are designed with that in mind.