All true. But I think it is just more the principle. If you need to cast the spell with a slot to get the full benefit, and it's a spell you'd only cast occasionally anyway, then why even make it a class feature? It doesn't even provide a ribbon beyond the preparation and generally worthless free cast.
You can look it as a free cast or as a free resurrection in a weakened state (with it being weaker only starting a level 9 and higher).
Now, a generous GM might allow you to cast it with a 3rd or higher spell slot and, if it disappears, cast it for free and say you are "summoning the steed that disappeared" and therefore using the same stat block. If you want to be kind, but not house rule casting without a spell slot at a higher level, that can be your justification.
You can look it as a free cast or as a free resurrection in a weakened state (with it being weaker only starting a level 9 and higher).
Now, a generous GM might allow you to cast it with a 3rd or higher spell slot and, if it disappears, cast it for free and say you are "summoning the steed that disappeared" and therefore using the same stat block. If you want to be kind, but not house rule casting without a spell slot at a higher level, that can be your justification.
How to add Tooltips.
My houserulings.