The Battle Cats

Yes, you can buy catfood

In the early gane you have to beat stages over and over to get treasures, and later you can grind to get tickets for the free gatcha, upgrade items, and exp to upgrade units

Yes, it can give in game currency and a permanent speed up along with an upgrade to make the speed up faster

Yes, there sre collabs that are on for a limited time, banners that are quite rare, and purchasable offers that can give units on the rare occasion, but usually just in game currency or items

There are some events that allow you to get specific units or upgrades that are daily, hourly, or for one event, a 2 minute window

While it isn't paying directly, you can use the in game currency (catfood) to skip timers, altho some timers can be bypassed for free thru catamins

It gets so many updates that if you somehow got to a near end state, another update will come out soon after adding more stages, forms for units, and units

Energy can be an issue in the early game, however later one can bypass this for free, but sending out an explorer known as gamatoto to get items takes time, and the otto corps take time to upgrade the base using materials.

It has login bonuses that allow to draw from the free gatcha (that can give you free roles on the paid gatcha) and sometimes they give out premium currency, units, and items

Kinda, if you gst far into the game it can feel.like you've put a lot of work into the game, plus if you uninstall the app without transferring data, you lose all of your progress