I feel like it's maybe that present tense gives less of a concrete sense of how much time is passing, which can work nicely for capturing a moment in detail without making readers hyper-aware that we've just spent X number of words on very little actually happening outside the characters' heads, but can also be used to create a surreal and dreamy feel where things are disconnected, or evoke a sense of days running together and characters being stuck in a rut or particular frame of mind. OTOH, I feel like something plotty or fast-paced like a mystery or action thriller that relies on things clicking together over a clear timeframe or wants to create a sense of urgency and race against the clock works better in past.
Re: X or Y
I feel like it's maybe that present tense gives less of a concrete sense of how much time is passing, which can work nicely for capturing a moment in detail without making readers hyper-aware that we've just spent X number of words on very little actually happening outside the characters' heads, but can also be used to create a surreal and dreamy feel where things are disconnected, or evoke a sense of days running together and characters being stuck in a rut or particular frame of mind. OTOH, I feel like something plotty or fast-paced like a mystery or action thriller that relies on things clicking together over a clear timeframe or wants to create a sense of urgency and race against the clock works better in past.