In my experience that reward trait hasn't made any difference at all with my writer Sims. You'd be better off getting 'Creative Visionary' and 'Marketable' if you're looking to buy a reward trait with satisfactions points.
Some ways to get inspired taken from a thread on Carl's The Sims 4 forum include:
Actions-Thoughtful shower / +1 4hrs
-Browsing art (Computer -> Web-> Browse Art) / +1 4hrs
-Making tea with Tea Magic Personal Brewer (after being upgraded, effect is random) / +2 4hrs
-Practice bar tricks / +1 4hrs
-View Bonsai (if the bonsai was shaped while inspired) / +1 4hrs
-Lump of Clay (item is portable making it convenient - inspiring blob) / +1 4hrs
Items-Reward Lamp: Ambitions / Aura
-Reward Lamp: Supernatural / Aura
-Postcards (regardless the amount of them) / +1
Career Awards (Writer)-Milton Word Processor /aura +2 ( computer as a reward for writer career level 2 !!)
-Still Life with Apple and Pitcher and Books and Bottles and Flowers!/aura +4 ( painting as a reward for writer career lvl 3)
-An Open Book - Framed- wall decoration/aura +5 ( writer career reward , lvl 5)
-Antique Tomes clutter /aura +5 ( writer career,author branch reward , lvl 6)
-Antique Writer's Desk/aura +5 ( writer career, journalist branch reward, lvl 7)
-The Where Should I Go? Ball -misc decoration/aura +8 (writer career,journalist branch reward , lvl 8 )
-Antique Typewriter statue /aura+8 ( writer career,journalist branch reward , lvl 9)
-Deep Thoughts Bookcase /aura +8 (writer career,journalist branch reward , lvl 10)
-Nom de Plume Quill Pen clutter/aura+6 (writer career,author branch reward , lvl 8 )
-The Muse Bookcase /aura +8 (writer career,author branch reward , lvl 9)
In addition, if you have the Outdoor Retreat GP, your Sim can Cloudgaze/Stargaze for a 6 hr. inspired moodlet and if you have the Spa Day GP, the yoga mat routine 'Brain Boosting' will give an 8 hr. inspired moodlet. That's all I can think of at the moment besides the above. Other Simmers might know of more.
There are many more ways to get inspired on that list, but I only posted the ones that were in general or in relation to the writing career. Here's a link to the thread if you want to take a look at the others:
Emotions and Items/Actions That Influence ThemJust so you know, the MySims trophies all come with a Playful moodlet aura when enabled and only a few crystals have emotion moodlets that can be enabled. I don't think any of them have inspired, mostly energetic. All fossils will give a 4 hr. focused moodlet when your Sim studies them.
Hope this helps! Happy Simming! <3
EDIT: Also, moodlets get a boost from any 'Happy' moodlets your Sims may have. So if you haven't already, I'd suggest upgrading some of your appliances/plumbing, have higher level paintings, furniture, etc. in the room where your Sim will be writing for the great environment decor boost and have your Sim do things that will make them 'happy.' There's a list on that thread I gave you for ways to get in all the emotions including 'Happy.'
