Time is precious. User time is more precious than developer time. It is a good investment to make end-user's experience faster and more pleasant, especially if there are millions of users. We do not insist to users that "patience is a virtue."
It is worth saving microseconds on a function if you run it a billion times a day, or 10k-100k+ times for a single user interaction.
Using a splash screen to mask a long load time is cheating. If it's unavoidable, then at least make the splash screen pleasant and memorable.
Don't make the computer, nor your users, duplicate effort.
If you can flip a switch that makes the software more performant or efficient, then flip the switch.
Degradation in software quality (performance, features, usability) spoils good will. Avoid.
Keep in mind that a single core of a modern CPU can, every second, move gigabytes of memory and perform billions of operations.