To answer your question and for any others that might come along to this thread;
Will it be a problem?
Denying access from the .htaccess file will block all connections unless permitted, so if you are using plugins that need to execute API calls or similar, you’ll need to whitelist those IPs.
So in totality, not really. Ultimately it depends on your site’s structure and the outbound/inbound connections it needs.
For completeness:
The following code prevents anyone from viewing your website depending on the version of apache you have running. Visitors will see a 403 Forbidden status while visiting your website.
Apache 2.2
Order deny,allow
Deny from all
Apache 2.4
Require all denied
It’s important to note, however, that using the above will inadvertently block you from accessing the directory also. To solve this you’ll likely want to use the following;
Apache 2.2
Order deny,allow
Deny from all
#Allow specific IP's...
allow from 127.0.0.1
Apache 2.4
Require local
Syntax
The syntax is sensitive so, order deny, allow should be order deny,allow (no space after ,) otherwise some Apache versions will show Server Error because order takes one argument, 'allow,deny', 'deny,allow' (Says Apache Log)
You can find your IP by using typing what is my ip into google.
Whereas 127.0.0.1 is a special-purpose IPv4 address and is called the localhost or loopback address. All computers use this address as their own, but it doesn’t let computers communicate with other devices as a real IP address does.
There’s plenty of info using these commands on the web, the bulk of the info posted here can be found in the following Stack thread.