Bitrefill, as a successful business, ought to switch to lightning.
They already support Lightning. But as per
their CEO's post here, Lightning transactions only make up around 15% of their business, while zero confirmation transactions make up 60%. This is a huge disparity. It's not enough to simply say "Use Lightning", when probably the majority of those 60% either have no experience with Lightning or aren't even holding their own coins at all.
More nodes that have Full RBF means more chances for everyone to establish connection with nodes that have Full RBF. Therefore, more chances for an attacker to take a user's transaction and hand it over to the miner.
Yes, but that doesn't matter if the miner in question is running their own node(s) which have full RBF disabled. Their nodes will reject such a transaction, and so the miner won't include it.