Splinterlands' share-your-battle-challenge really gets me one way or another any week.
Last week's featured unit had such a high price I could only afford to rent it, but "unfortunately" I had enough liquid funds to buy Nerissa Tridawn, this week. She has been on my watchlist for a while, so I went ahead and bought her.

Hopefully my purchase was worth it! -Let's see! :D

These are my thoughts on Nerissa Tridawn which is an Epic card of Water Splinter:
first thought (-): 9 mana cost, this card does not come cheap in terms of mana.
second thought (+): 3 magic damage which is really a blast (for your opponent's units, too)!
third thought (+): 9 health which is more than nice to have.
fourth thought (-): 2 initiative is somehow unusually low for Water Spinter, but this is not a deal breaker for me.

Adding my thoughts when leveling up Nerissa
regarding her stats development: It is very nice to see that her main selling-points for me (both magic attack and high health) can be developed even further up to 5(!) magic damage and 11 health.
regarding her (missing) abilities: Sure an ability might make her even better in specific rule-sets. But to me her lack of abilities is only something worth noticing, but really no big issue, though.

Let us go for one of my battles including my newly purchased Nerissa Tridawn:
https://splinterlands.com?p=battle&id=sl_669cc0643d019997093b4fc973c5a52a&ref=jdike

Hard facts: Modern format, 25 Mana Cap, Additional rules: 'Heavy Hitters'

The setup: I don't know if I encountered some kind of alt-account playing only gold cards, but I had one on the field, as well! ;)

Still my opponent went with a mixed Life Splinter setup with Portal Spinner as heavy-hitter who was further boosted by General Sloan.
My idea was to focus on Oshannus and Nerissa supported by a healer.

Round 1 saw my frontrow units leaving the field and Nerissa giving an idea of her strength. If only her initiative had been higher and she would have activated prior to opponent's healer, my opponent's main tank would already be gone.
Still her 3 magic damage paved the way...

...for Oshannus to take down the enemy tank and for Nerissa to take down the Celestial Harpy, only momemts later.

Round 3 and 4 went on about the same and the opponent's units were not able to withstand my 5 magical damage per round.
At the latest in round 4 the battle had been decided, when there was only one enemy ranged unit left on the field that could still deal damage.

So you might ask was buying Nerissa worth it? -I think so! With her low initiative she somewhat falls out of line in Water Splinter, but her uneven 3 magical damage really gives an edge in some battles! As you have seen above a single attack of her is more than often enough to take down an opponent's low mana units single-handedly.
Furthermore unlike other units Nerissa's usefullness is not limited to a few very specific rulesets. She just offers your line-up some firepower. For this reason I am happy with my purchase as Nerissa will strengthen my Water Splinter decks!

If you are not yet into Splinterlands feel free to use my sign-up link:
https://splinterlands.com?ref=jdike