>>1769263
Depends what the focus of the game is.
>combat focus with new characters introduced constantly
Very important for the character to have a good kit and appealing appearance and personality to be worth it
>Story/Romance focused with a set amount of characters in a rotation
Very important to have quality writing, that includes tropes and visuals to keep me hooked

Rule of thumb I only spend money on characters I love and feel like are worth supporting. Current fish myth is a good example to r3. Amazing myth story, beautiful visuals and a very strong battle kit.
For BL games like nucarni I only throw money at 2 characters, the game is easier to just ignore banners if you're not interested, so my money is usually safe. I would spend more money if devs had more quality content but the rooms are too short in my opinion and I hate that room 1+3-4 aren't voiced.
For omnigames the last time I whaled was in gbf, probably threw max 20bucks at genshin and 30 at HSR for a battlepass to get icons in December and then never again. By far the worst game to spend money in.