If you don't use core, then they aren't your Bitcoins. It's the same as money deposited in a fiat bank.
If you don't want to tie up 200Gb, then run a pruned node. You lose a few functions, but save a lot of drive space. If you haven't got the drive space available, then use an external SSD.
Good line. I don't have enough knowledge on BTC core too, so that's it. I wonder if that core is consuming a lot of data, and what is the requirements of the PC to run that?
I'm willing to download this.
It is a good line, very eye catching, but a bit incorrect

As I said, you and only you still have full control of your coins when you are using Electrum and the drawback is not that big to be honest.
But it is a lot better to run Core for multiple reasons and security,privacy and helping the network is one of these.
Bitcoin Core takes few hundred MB of RAM and couple of tens of KB/s bandwith. The blockchain is around 170GB now, but it is always increasing so I would count around 200GB. However you can have a pruned node that can take as much as space as you define. It doesn't take much CPU power either and when it does it is usually small spikes every 10 minutes or so, when the new block comes.
It will just take some time to sync first time you start it as it needs to download and verify the entire blockchain. This is largely up to your CPU speed and it often take around a week.
So I need to have a midrange-high CPU in order to run this ? (i7-i3)? And my computer will run for about a week? (what if i turn off the computer will it continue to sync the from the end when I turned off the computer?) I have a lot to learn on this one (may be a I should build a new computer rig again and subscribe for a more stable internet connection).
By the way I did some research on the requirements of the computer in downloading BTC core :
Minimum Recommended
Disk space. 145 GB.
Download. 500 MB/day (15 GB/month)*
Upload. 5 GB/day (150 GB/month)
Memory (RAM) 1 GB.
System. Desktop. Laptop. Some ARM chipsets >1 GHz.
Operating system. Windows 7/8.x/10. Mac OS X. Linux.
source : https://bitcoin.org/en/bitcoin-core/features/requirementsThe requirements are not that expensive but the data is another story.
And yes based from what I've heard you can have some viruses but if you will run it on windows your computer anti virus might affect the performance.
So i need to run some linux (I need to learn).
Thank you for your answer by the way. It helps.