If I understand it correctly, the chance to pull a Legendary is still the same, the chance of said Legendary being Siphi is 10x, so keep that in mind. Do you keep track of your mercy counter at all? It becomes helpful at times like this. 

Don't waste your shards. Your odds are miniscule. 

Listen to kram

i will save the shards.  Thx for the advice.  

Id use 1 , maybe 2 ... ive had insane luck early on ... 

There was a double leggo on ancient , and i decided to pull my only ancient back then ... Pulled lyssandra and warchief ... 

Id say these 10x events are the perfect time to test your luck and use 1 , maybe 2 shards , while keeping the rest since the odds are still super small ... aint a 75x but a 10x !

TLDR : 10x perfect time to pull just 1 or 2 and get that gambling feeling but arent worth fully investing in !

Don't gamble :)

I knew I was due a leggo on Sacreds, so I pulled a Rotos. I know I am due for a Leggo in Voids in about 20-25 pulls, so if some void packs come up, I may bite the bullet. But otherwise, it's a fool's errand chasing champs during 10X.

but thats what its all about with these gacha game :P key is gambling with super moderation ;)

Listen to Trips

Its my bday today.  I pulled one void shard.  Got Inquisitor Shameal.  Not what I wanted but not a common rare either.  

Bad decision, good result.  Happy birthday  :)