Which spell would you be using?
Personally, I would probably just use Truestrike but this could be Flame Blade, Chromatic Orb, or Vampiric Touch; or any other attack roll spell from the Bard, Cleric, Druid, or Wizard lists.
Using a higher level slot out damages a cantrip easily enough, and can have additional effects.
It depends on what the player likes. The important part is to take something that uses attack rolls so that this part of the feature can be used.
Of course. Never said you shouldn't play a Lore bard.
I'm just saying it's mildly weaker than the other subclasses. Because Bardic Inspiration, Cutting Words, and Peerless Skill compete for the same resource.
That's still true for other bard subclass abilities. Additional skill proficiencies don't, and Magical Discoveries may not.
I would be playing this for two reasons. The skill benefits, and personal use Cutting Words and Peerless Skill provide.
Dance bards and Glamour bards get their best BI uses with other party members. Valor bards get useful abilities but their BI dice are still focused on the party.
That's not a bad thing, but Lore bard's can operate their BI dice more independent from others. Bit of a selfish college
You just need something worth spamming.
The player chooses what they want to use. Taking actions that trigger checks is within player agency.
If I want it to be Acrobatics my PC will do things that will likely trigger those checks as an example. It doesn't have to be the same skill repeatedly.
The more actions attempted the more checks the more failures the more replacement the more successes. That's just a numbers game.
There is a bit of "DM may I?" That depends on what the player attempts. But this type of character and style of play can crush stealth, lore, and social activities.