From what I've read, Bitcoin now charges high transaction fee and long transaction wait time so it can't presently be used:
a) for a conversion from Bitcoin to cash?
or b) purchases using Bitcoin?

Well there are some apps that provided me the convenience for those. I can convert mine easily to cash.
Purchasing using Bitcoin isn't that much of a problem because I can't pretty much just do the conversion then pay through the converted amount.
If you reside in PH, you can use Coins.ph app.