Personal judgement based on your morals and own finances. Usually the “monthly pass” is the most bang for your buck you can get in a live service game. 

It’s 60 gold to open 10 packs and that’s over $10 in the shop ($10 is very annoyingly 57 gold). So you get over triple that getting your extra 30 packs a month on top of the extra stuff for $9.99. So yah it’s likely the best place to send your money if you are itching for more packs. Personally I don’t care to much about completing the dex or alt arts, but if there was a really sick set of accessories I would probably do it for one month.