blockchain.info's wallet allows (or used to) one to access funds on the above, but it has been a long time since I did that, and I do not know if more modern versions still allow that.
You can still do that in "Settings Icon->Wallets & Addresses", below the page, there's an "Import Bitcoin Addresses" button, you can paste a compressed private key instead if you want it to be spendable.You have the option to "Transfer funds to an existing wallet" (sweep) it to your existing wallet or not, if not "swept" you'll have an option to select that wallet in the 'send' page.
But there's a limitation: you can only import legacy addresses, not SegWit or P2SH.
The consensus here is to keep away from an online wallets anyways, but it's up to you..
That's good information, thank you.
An online wallet is useful if you do not want to carry around a hardware one. The paper wallet / card / OpenDime offer certain special advantages in my case. Having the option of getting BTC out when, for example, overseas, can be useful in my situation.
Also good info on only being able to import legacy addresses. Thanks again.
